Moose the Fat Cat
Member
What/why is this thread?
This is separate from Suggestions for the SRB2 team. Instead, these are just pitches for original Sonic fangames you think would be cool, and describing how they would work. This is for ideas we're unable to execute by ourselves, but are fun to "design" theoretically with our inherent designing/directing/writing/producing skills.
Who knows, maybe a Sonic fan with programming skills reads this thread and is intrigued by a pitch? That's the best possible outcome of this thread -- it leads to new projects and connections. That's the ceiling, but the floor is much lower — anybody is free to post their idea, and the guiding principle is that thinking creatively is its own reward.
Rules
Prompts (template)
The Big Idea:(what's your goal with this game? how is it different from what exists, and why would you like to play it?)
Mod Engine: (which existing game are you building from to modify? ie: Doom Legacy, or Hedgehog Engine, or Mania/Retro engine)
Genre: (short classification of the gameplay; ie: 2D sidescroller; 2D metroidvania; 3D open world objective-based; 3D platformer courses; etc)
Gameplay and Levels: (how does it work? who are the characters? what are the abilities/buttons? what are the objectives? are there special stages? are you porting existing levels, or creating new ones from modified assets? describe the campaign as brief or as detailed as you prefer; if there's a story alongside the level progression, this is where to tell us.)
Story Objective: (briefly, what's at stake? ie: stop Eggman's new weapon and collect emeralds; time travel to destroy the new Death Egg from destroying the world; rescue Big the Cat from Tails Doll; whatever)
Title: (lastly, what's this game called?)
My Pitch(Full pitch in the spoiler tags)
---------- Post added at 12:51 AM ---------- Previous post was at 12:21 AM ----------
Expanding on the Level Design:
I haven't played the majority of the Boost games to completion, so I actually don't know what the best Boost levels would be, exactly. Even just stacking together the levels I have played of Boost in Generations/Forces, without menus or anything in-between to interrupt, would be a much more solid overall experience than any of the games on their own.
I haven't played Unleashed to completion, and don't plan to; the game seems like it's conceptually interesting but a bit of a disaster in execution. Simply splitting up the 2 styles in 2 separate campaigns allows each distinct flavor to be enjoyed on its own. Rather than forcing the player to go between the two haphazardly, the player chooses which they want to play.
Boost and Beat-Em-Up, in the same package, but separated. Each is simple/intuitive/easily accessible and shareable with other players. It's easy to pick-up either, but there's a high ceiling for mastery in speed running and finding every secret.
The wide, wacky sea of extended Sonic cast can be easily justified & provide value (in Beat-Em-Up as back-up buddies for Knuckles) while keeping the core focus tight on Sonic & Eggman.
Though Boost should stay limited to 2P/split-screen or 2P/online, there's less need to limit that for Beat Em Up stages. Assuming the engine could handle it, 4 player Beat Em Up would be super fun. Each additional player after 2 doubles the amount of enemies to compensate.
This is separate from Suggestions for the SRB2 team. Instead, these are just pitches for original Sonic fangames you think would be cool, and describing how they would work. This is for ideas we're unable to execute by ourselves, but are fun to "design" theoretically with our inherent designing/directing/writing/producing skills.
Who knows, maybe a Sonic fan with programming skills reads this thread and is intrigued by a pitch? That's the best possible outcome of this thread -- it leads to new projects and connections. That's the ceiling, but the floor is much lower — anybody is free to post their idea, and the guiding principle is that thinking creatively is its own reward.
Rules
Three C's:
1. Creative pitches must factor in production realities. This is why the prompts ask for engine, gameplay, and levels. There's plenty of existing accessible assets to build from, both within Sega Sonic games, and otherwise (like SRB2 building from Doom/Legacy, your fangame might build from modding Mario Sunshine to incorporate Sonic)
2. Criticism should be constructive and golden-ruled. Opinions and preferences are like onions and fried pickles -- an acquired taste and should be served sparingly ;)
3. Collaboration is a form of flattery. A programmer who might be interested in a mod pitch ought to DM or reach out to the original poster as a kind of creative partner or acknowledge your interest in contributing toward that project in a small way ("I like that idea; I could do some model/sprite re-coloring since I've been doing that on my own project") as that could be the thing that gets the snowball rolling in unforeseen ways but builds momentum all the same.
Disclaimer:
Obviously none of us own Sega's IP so it's not technically possible to "steal" any of the ideas in this thread. It's not that this hypothetical Ayn Randian programmer needs permission from the poster to expand on the idea and execute on their own (the programmer likely thought of whatever this idea is before, just not in this specific way) -- it's that if you acknowledge this idea has value, it's just good form to give praise where it's due, and idk, team work can make the dream work. Soft and hard skills are best applied together.
1. Creative pitches must factor in production realities. This is why the prompts ask for engine, gameplay, and levels. There's plenty of existing accessible assets to build from, both within Sega Sonic games, and otherwise (like SRB2 building from Doom/Legacy, your fangame might build from modding Mario Sunshine to incorporate Sonic)
2. Criticism should be constructive and golden-ruled. Opinions and preferences are like onions and fried pickles -- an acquired taste and should be served sparingly ;)
3. Collaboration is a form of flattery. A programmer who might be interested in a mod pitch ought to DM or reach out to the original poster as a kind of creative partner or acknowledge your interest in contributing toward that project in a small way ("I like that idea; I could do some model/sprite re-coloring since I've been doing that on my own project") as that could be the thing that gets the snowball rolling in unforeseen ways but builds momentum all the same.
Disclaimer:
Obviously none of us own Sega's IP so it's not technically possible to "steal" any of the ideas in this thread. It's not that this hypothetical Ayn Randian programmer needs permission from the poster to expand on the idea and execute on their own (the programmer likely thought of whatever this idea is before, just not in this specific way) -- it's that if you acknowledge this idea has value, it's just good form to give praise where it's due, and idk, team work can make the dream work. Soft and hard skills are best applied together.
Prompts (template)
The Big Idea:(what's your goal with this game? how is it different from what exists, and why would you like to play it?)
Mod Engine: (which existing game are you building from to modify? ie: Doom Legacy, or Hedgehog Engine, or Mania/Retro engine)
Genre: (short classification of the gameplay; ie: 2D sidescroller; 2D metroidvania; 3D open world objective-based; 3D platformer courses; etc)
Gameplay and Levels: (how does it work? who are the characters? what are the abilities/buttons? what are the objectives? are there special stages? are you porting existing levels, or creating new ones from modified assets? describe the campaign as brief or as detailed as you prefer; if there's a story alongside the level progression, this is where to tell us.)
Story Objective: (briefly, what's at stake? ie: stop Eggman's new weapon and collect emeralds; time travel to destroy the new Death Egg from destroying the world; rescue Big the Cat from Tails Doll; whatever)
Title: (lastly, what's this game called?)
My Pitch(Full pitch in the spoiler tags)
This one's adapted from a post on another board about the official games...
(I have at least 3 others that I've already pitched elsewhere just on this board)
The Big Idea One major thing official modern Sonic gets wrong in the translation of the Genesis spirit (in addition to a thousand other things) is the lack of optional 2P co-op.
In 2/3/K/M, Tails as the invincible but optional helper allows the 2P sibling/roommate/partner to jump in and out at will, without ruining the flow of the 1P progression. At their least helpful, the 2P/CPU is a background distraction; at their most helpful, the 2P can cheese difficult bosses/enemies and carry you across difficult sections.
This exponentially increases the game's accessibility, beyond just making the game as easy or difficult as you prefer on the fly in any level (more on that in a moment). The casual player can help as 2P with no skills/no tutorial because their actions are entirely bonus to the 1P, and also helps 2P learn to play and eventually start their own 1P campaign.
It also justifies and leverages the expansive Sonic cast to greater effect ever.
Mod Engine: Hedgehog Engine with the Unleashed Werehog night stages reskinned with new characters and Boost levels cherry-picked from multiple games.
Genre
3D action/adventure with co-op. 2 campaigns -- Boost, using available levels (a selection of the best of Unleashed/Colors/Generations/Forces) and Battle, using the fighting levels from Unleashed in re-skinned stages with new characters.
Gameplay and Levels
From the start screen, we're prompted to choose a Campaign from two options:
—Sonic (Boost levels)
—Knuckles (Battle levels)
—(Final, which unlocks after both are completed for first time)
Sonic / Boost
Two sticks, Two triggers, Two buttons
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Boost (down+A in mid-air = stomp; down+A )
(B+B= Homing if enemy targeted, Air Dash/Thok if not)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
Knuckles / Battle
Two buttons, Two sticks, Two triggers
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Attack (for Knuckles, this is punch)
(B+B= Gliding or Stick/Climb)
(B+A= Downward Dig)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
The co-op characters vary in how those moves look and rate of speed / damage they possess (Sonic is best, meaning the other characters are all a bit more difficult to play as because they're relatively less fast/powerful), but functionally they're all the same.
Co-Op
1P is Sonic or Knuckles by default; both are the most powerful (and easiest) characters in their category. After completing a campaign once, 1P unlocks the ability to choose from all of the co-op Characters, and Sonic/Knuckles become accessible for 2P/CPU.
2P/CPU co-op can be added at any time from the opening or pause menu, chosen from a selection of characters. If the co-op character appears mid-stage from the menu, they drop from a Warp Ring to where the player is.
Only for the Sonic stages, 2P splits the screen vertically (default) like co-op version of SA2:Battle; this doesn't happen if Sonic's co-op is CPU. For the Knuckles stages, both players share the same screen.
The Pause Menu is justified by the new design of looking like a Goldeneye/Bond spy watch. The most prominent option is Back-Up
Back-Up opens quick small prompts:
-2P or CPU
-Character
-Helper (easy), Tag Along (default), or Challenge (hard)
Helper means the CPU aggressively takes care of as many level challenges for the player as needed. Killing all enemies around you, and warping to you to offer a carry over any chasm. It is super-baby mode and even beginner players will probably not want this on all the time. For 2P, Helper means that in addition to their infinite lives, 2P has default invincibility from enemies/spikes.
Tag Along is default, CPU are more like followers in Mania, they sometimes help but mostly they're just dummies who follow you. For 2P, they have infinite lives, but otherwise it's like they are playing 1P. The level is complete as soon as either one reaches the finish; the other player is given the option to finish or take a Warp Ring to the end. (You can easily cheat by playing 2P alone, keeping 1P Sonic tapping his foot, and play the overpowered 2P co-op to completion. The game shouldn't bother with any effort to prevent that, because it's just obviously a bit... pathetic to play that way; so if you really want to then more power to you. The idea is for the girlfriend/sibling/roommate 2P to be able to have fun and contribute without getting frustrated needing to learn how to play. They can just press buttons and do okay if they're terrible, and if they're even a little skilled, it can be a lot of fun to team up throughout the level)
Challenge is instant hard mode with the CPU. Once it's chosen (must be from before the mid-way point of the level), it can't be un-chosen until you win or give up. It adds in the co-op character, along with a new level incentive -- to race to the finish and complete the stage before they do. If CPU wins, it's back to the very beginning of the level (give up the challenge? or try again?).
Back-Up (Co-Op Characters)
If you play entirely solo, it's simply you as Sonic or Knuckles through a full campaign, the other characters appearing in skippable cut scenes, then the others are playable as unlockables.
Sonic's co-op 2P/CPU can choose from Tails; Shadow; Blaze. (Tails is in a small jet, Tornado III aka T3-Jet, allowing him to Boost.) Any of the 3 can be set to any of the 3 settings (Tagalong, Helper, Competitor). Not all CPU competitors are equally difficult. (Story-wise, Shadow and Blaze have their own motivations but cross paths with Sonic & Tails having the same basic objective.)
Knuckles' co-op 2P/CPU can have a much wider selection of available player characters. The battle campaign is about fighting back the worldwide invasion of Dark Gaia monsters while Knuckles searches for the Chaos Emeralds and Sonic searches for the Shrines.
Any character who could attack can work -- Amy Rose; Silver; Fang; Rouge; Vector; Espio; Big the Cat; Mighty; Tails in T3-Mech shooter; Shadow; Blaze. They arrive via Warp Ring, either way. The only character who cannot be there is Sonic the Hedgehog, only Sonic the Werehog.
Story Objective
We'll adapt the story loosely from Flynn's Shattered World arc in Archie, adjusting for what's already available in the games. Since we're rewriting the story, the text will change the most — so voice acting is eliminated or replaced.
Except the opening cinematic from Unleashed, which is still perfect. No need to cut the voice acting here since it's great, but following this scene, all dialogue is cut (except for Eggman threats in battles). Title screen is new: SONIC & KNUCKLES 3D.
Sonic & Tails (with Chip as a passenger in Tails' T3 jet) are on the trail of the Gaia Temples and, along the way, rescue humans/animals in need. Blaze and Agent Shadow are both on the trail too, each with their own motivations to fix the shattered world, but all having the same end goal, so they team up with Sonic along the way while otherwise keeping to their separate paths.
Knuckles is hunting for the Chaos Emeralds while leading the fight against the Dark Gaia monsters. Amy Rose is coordinating both teams through the spy watches, and arranging back-up as necessary depending on who's nearby (ie, who the player chooses).
Knuckles' stages aren't all night. If Sonic the Werehog is chosen as the CPU/2P co-op, it's the presence of strong Dark Gaia energy that brings about the transformation.
(If "Sonic" is completed first, the Gaia Temples are marked complete by Warp Rings. If "Sonic" is completed second, then he has the Emeralds to place in the altar. If "Knuckles" is completed first, Knuckles holds onto the Emeralds until Sonic finds the Temples. If "Knuckles" is completed second, Knuckles takes a Warp Ring to the nearest Temple to place the Emerald at the end of the stage.)
Title
Sonic & Knuckles 3D
(I have at least 3 others that I've already pitched elsewhere just on this board)
The Big Idea One major thing official modern Sonic gets wrong in the translation of the Genesis spirit (in addition to a thousand other things) is the lack of optional 2P co-op.
In 2/3/K/M, Tails as the invincible but optional helper allows the 2P sibling/roommate/partner to jump in and out at will, without ruining the flow of the 1P progression. At their least helpful, the 2P/CPU is a background distraction; at their most helpful, the 2P can cheese difficult bosses/enemies and carry you across difficult sections.
This exponentially increases the game's accessibility, beyond just making the game as easy or difficult as you prefer on the fly in any level (more on that in a moment). The casual player can help as 2P with no skills/no tutorial because their actions are entirely bonus to the 1P, and also helps 2P learn to play and eventually start their own 1P campaign.
It also justifies and leverages the expansive Sonic cast to greater effect ever.
Mod Engine: Hedgehog Engine with the Unleashed Werehog night stages reskinned with new characters and Boost levels cherry-picked from multiple games.
Genre
3D action/adventure with co-op. 2 campaigns -- Boost, using available levels (a selection of the best of Unleashed/Colors/Generations/Forces) and Battle, using the fighting levels from Unleashed in re-skinned stages with new characters.
Gameplay and Levels
From the start screen, we're prompted to choose a Campaign from two options:
—Sonic (Boost levels)
—Knuckles (Battle levels)
—(Final, which unlocks after both are completed for first time)
Sonic / Boost
Two sticks, Two triggers, Two buttons
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Boost (down+A in mid-air = stomp; down+A )
(B+B= Homing if enemy targeted, Air Dash/Thok if not)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
Knuckles / Battle
Two buttons, Two sticks, Two triggers
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Attack (for Knuckles, this is punch)
(B+B= Gliding or Stick/Climb)
(B+A= Downward Dig)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
The co-op characters vary in how those moves look and rate of speed / damage they possess (Sonic is best, meaning the other characters are all a bit more difficult to play as because they're relatively less fast/powerful), but functionally they're all the same.
Co-Op
1P is Sonic or Knuckles by default; both are the most powerful (and easiest) characters in their category. After completing a campaign once, 1P unlocks the ability to choose from all of the co-op Characters, and Sonic/Knuckles become accessible for 2P/CPU.
2P/CPU co-op can be added at any time from the opening or pause menu, chosen from a selection of characters. If the co-op character appears mid-stage from the menu, they drop from a Warp Ring to where the player is.
Only for the Sonic stages, 2P splits the screen vertically (default) like co-op version of SA2:Battle; this doesn't happen if Sonic's co-op is CPU. For the Knuckles stages, both players share the same screen.
The Pause Menu is justified by the new design of looking like a Goldeneye/Bond spy watch. The most prominent option is Back-Up
Back-Up opens quick small prompts:
-2P or CPU
-Character
-Helper (easy), Tag Along (default), or Challenge (hard)
Helper means the CPU aggressively takes care of as many level challenges for the player as needed. Killing all enemies around you, and warping to you to offer a carry over any chasm. It is super-baby mode and even beginner players will probably not want this on all the time. For 2P, Helper means that in addition to their infinite lives, 2P has default invincibility from enemies/spikes.
Tag Along is default, CPU are more like followers in Mania, they sometimes help but mostly they're just dummies who follow you. For 2P, they have infinite lives, but otherwise it's like they are playing 1P. The level is complete as soon as either one reaches the finish; the other player is given the option to finish or take a Warp Ring to the end. (You can easily cheat by playing 2P alone, keeping 1P Sonic tapping his foot, and play the overpowered 2P co-op to completion. The game shouldn't bother with any effort to prevent that, because it's just obviously a bit... pathetic to play that way; so if you really want to then more power to you. The idea is for the girlfriend/sibling/roommate 2P to be able to have fun and contribute without getting frustrated needing to learn how to play. They can just press buttons and do okay if they're terrible, and if they're even a little skilled, it can be a lot of fun to team up throughout the level)
Challenge is instant hard mode with the CPU. Once it's chosen (must be from before the mid-way point of the level), it can't be un-chosen until you win or give up. It adds in the co-op character, along with a new level incentive -- to race to the finish and complete the stage before they do. If CPU wins, it's back to the very beginning of the level (give up the challenge? or try again?).
Back-Up (Co-Op Characters)
If you play entirely solo, it's simply you as Sonic or Knuckles through a full campaign, the other characters appearing in skippable cut scenes, then the others are playable as unlockables.
Sonic's co-op 2P/CPU can choose from Tails; Shadow; Blaze. (Tails is in a small jet, Tornado III aka T3-Jet, allowing him to Boost.) Any of the 3 can be set to any of the 3 settings (Tagalong, Helper, Competitor). Not all CPU competitors are equally difficult. (Story-wise, Shadow and Blaze have their own motivations but cross paths with Sonic & Tails having the same basic objective.)
Knuckles' co-op 2P/CPU can have a much wider selection of available player characters. The battle campaign is about fighting back the worldwide invasion of Dark Gaia monsters while Knuckles searches for the Chaos Emeralds and Sonic searches for the Shrines.
Any character who could attack can work -- Amy Rose; Silver; Fang; Rouge; Vector; Espio; Big the Cat; Mighty; Tails in T3-Mech shooter; Shadow; Blaze. They arrive via Warp Ring, either way. The only character who cannot be there is Sonic the Hedgehog, only Sonic the Werehog.
Story Objective
We'll adapt the story loosely from Flynn's Shattered World arc in Archie, adjusting for what's already available in the games. Since we're rewriting the story, the text will change the most — so voice acting is eliminated or replaced.
Except the opening cinematic from Unleashed, which is still perfect. No need to cut the voice acting here since it's great, but following this scene, all dialogue is cut (except for Eggman threats in battles). Title screen is new: SONIC & KNUCKLES 3D.
Sonic & Tails (with Chip as a passenger in Tails' T3 jet) are on the trail of the Gaia Temples and, along the way, rescue humans/animals in need. Blaze and Agent Shadow are both on the trail too, each with their own motivations to fix the shattered world, but all having the same end goal, so they team up with Sonic along the way while otherwise keeping to their separate paths.
Knuckles is hunting for the Chaos Emeralds while leading the fight against the Dark Gaia monsters. Amy Rose is coordinating both teams through the spy watches, and arranging back-up as necessary depending on who's nearby (ie, who the player chooses).
Knuckles' stages aren't all night. If Sonic the Werehog is chosen as the CPU/2P co-op, it's the presence of strong Dark Gaia energy that brings about the transformation.
(If "Sonic" is completed first, the Gaia Temples are marked complete by Warp Rings. If "Sonic" is completed second, then he has the Emeralds to place in the altar. If "Knuckles" is completed first, Knuckles holds onto the Emeralds until Sonic finds the Temples. If "Knuckles" is completed second, Knuckles takes a Warp Ring to the nearest Temple to place the Emerald at the end of the stage.)
Title
Sonic & Knuckles 3D
---------- Post added at 12:51 AM ---------- Previous post was at 12:21 AM ----------
What/why is this thread?
My Pitch(Full pitch in the spoiler tags)
This one's adapted from a post on another board about the official games...
(I have at least 3 others that I've already pitched elsewhere just on this board)
The Big Idea One major thing official modern Sonic gets wrong in the translation of the Genesis spirit (in addition to a thousand other things) is the lack of optional 2P co-op.
In 2/3/K/M, Tails as the invincible but optional helper allows the 2P sibling/roommate/partner to jump in and out at will, without ruining the flow of the 1P progression. At their least helpful, the 2P/CPU is a background distraction; at their most helpful, the 2P can cheese difficult bosses/enemies and carry you across difficult sections.
This exponentially increases the game's accessibility, beyond just making the game as easy or difficult as you prefer on the fly in any level (more on that in a moment). The casual player can help as 2P with no skills/no tutorial because their actions are entirely bonus to the 1P, and also helps 2P learn to play and eventually start their own 1P campaign.
It also justifies and leverages the expansive Sonic cast to greater effect ever.
Mod Engine: Hedgehog Engine with the Unleashed Werehog night stages reskinned with new characters and Boost levels cherry-picked from multiple games.
Genre
3D action/adventure with co-op. 2 campaigns -- Boost, using available levels (a selection of the best of Unleashed/Colors/Generations/Forces) and Battle, using the fighting levels from Unleashed in re-skinned stages with new characters.
Gameplay and Levels
From the start screen, we're prompted to choose a Campaign from two options:
—Sonic (Boost levels)
—Knuckles (Battle levels)
—(Final, which unlocks after both are completed for first time)
Sonic / Boost
Two sticks, Two triggers, Two buttons
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Boost (down+A in mid-air = stomp; down+A )
(B+B= Homing if enemy targeted, Air Dash/Thok if not)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
Knuckles / Battle
Two buttons, Two sticks, Two triggers
L stick -- forward/backward/strafe
R stick -- camera/vision
L1 -- sidestep left (hard left if L1+left)
R1 -- sidestep right (hard right if R1+right)
B -- Jump
A -- Attack (for Knuckles, this is punch)
(B+B= Gliding or Stick/Climb)
(B+A= Downward Dig)
(Back/Down + A in mid-air =Stomp)
(Back/Down + A on ground= Roll)
(While rolling, press A again to Spin Dash; hold to charge Spin Dash; aim with R; release A to fire the spinball and L to aim)
The co-op characters vary in how those moves look and rate of speed / damage they possess (Sonic is best, meaning the other characters are all a bit more difficult to play as because they're relatively less fast/powerful), but functionally they're all the same.
Co-Op
1P is Sonic or Knuckles by default; both are the most powerful (and easiest) characters in their category. After completing a campaign once, 1P unlocks the ability to choose from all of the co-op Characters, and Sonic/Knuckles become accessible for 2P/CPU.
2P/CPU co-op can be added at any time from the opening or pause menu, chosen from a selection of characters. If the co-op character appears mid-stage from the menu, they drop from a Warp Ring to where the player is.
Only for the Sonic stages, 2P splits the screen vertically (default) like co-op version of SA2:Battle; this doesn't happen if Sonic's co-op is CPU. For the Knuckles stages, both players share the same screen.
The Pause Menu is justified by the new design of looking like a Goldeneye/Bond spy watch. The most prominent option is Back-Up
Back-Up opens quick small prompts:
-2P or CPU
-Character
-Helper (easy), Tag Along (default), or Challenge (hard)
Helper means the CPU aggressively takes care of as many level challenges for the player as needed. Killing all enemies around you, and warping to you to offer a carry over any chasm. It is super-baby mode and even beginner players will probably not want this on all the time. For 2P, Helper means that in addition to their infinite lives, 2P has default invincibility from enemies/spikes.
Tag Along is default, CPU are more like followers in Mania, they sometimes help but mostly they're just dummies who follow you. For 2P, they have infinite lives, but otherwise it's like they are playing 1P. The level is complete as soon as either one reaches the finish; the other player is given the option to finish or take a Warp Ring to the end. (You can easily cheat by playing 2P alone, keeping 1P Sonic tapping his foot, and play the overpowered 2P co-op to completion. The game shouldn't bother with any effort to prevent that, because it's just obviously a bit... pathetic to play that way; so if you really want to then more power to you. The idea is for the girlfriend/sibling/roommate 2P to be able to have fun and contribute without getting frustrated needing to learn how to play. They can just press buttons and do okay if they're terrible, and if they're even a little skilled, it can be a lot of fun to team up throughout the level)
Challenge is instant hard mode with the CPU. Once it's chosen (must be from before the mid-way point of the level), it can't be un-chosen until you win or give up. It adds in the co-op character, along with a new level incentive -- to race to the finish and complete the stage before they do. If CPU wins, it's back to the very beginning of the level (give up the challenge? or try again?).
Back-Up (Co-Op Characters)
If you play entirely solo, it's simply you as Sonic or Knuckles through a full campaign, the other characters appearing in skippable cut scenes, then the others are playable as unlockables.
Sonic's co-op 2P/CPU can choose from Tails; Shadow; Blaze. (Tails is in a small jet, Tornado III aka T3-Jet, allowing him to Boost.) Any of the 3 can be set to any of the 3 settings (Tagalong, Helper, Competitor). Not all CPU competitors are equally difficult. (Story-wise, Shadow and Blaze have their own motivations but cross paths with Sonic & Tails having the same basic objective.)
Knuckles' co-op 2P/CPU can have a much wider selection of available player characters. The battle campaign is about fighting back the worldwide invasion of Dark Gaia monsters while Knuckles searches for the Chaos Emeralds and Sonic searches for the Shrines.
Any character who could attack can work -- Amy Rose; Silver; Fang; Rouge; Vector; Espio; Big the Cat; Mighty; Tails in T3-Mech shooter; Shadow; Blaze. They arrive via Warp Ring, either way. The only character who cannot be there is Sonic the Hedgehog, only Sonic the Werehog.
Story Objective
We'll adapt the story loosely from Flynn's Shattered World arc in Archie, adjusting for what's already available in the games. Since we're rewriting the story, the text will change the most — so voice acting is eliminated or replaced.
Except the opening cinematic from Unleashed, which is still perfect. No need to cut the voice acting here since it's great, but following this scene, all dialogue is cut (except for Eggman threats in battles). Title screen is new: SONIC & KNUCKLES 3D.
Sonic & Tails (with Chip as a passenger in Tails' T3 jet) are on the trail of the Gaia Temples and, along the way, rescue humans/animals in need. Blaze and Agent Shadow are both on the trail too, each with their own motivations to fix the shattered world, but all having the same end goal, so they team up with Sonic along the way while otherwise keeping to their separate paths.
Knuckles is hunting for the Chaos Emeralds while leading the fight against the Dark Gaia monsters. Amy Rose is coordinating both teams through the spy watches, and arranging back-up as necessary depending on who's nearby (ie, who the player chooses).
Knuckles' stages aren't all night. If Sonic the Werehog is chosen as the CPU/2P co-op, it's the presence of strong Dark Gaia energy that brings about the transformation.
(If "Sonic" is completed first, the Gaia Temples are marked complete by Warp Rings. If "Sonic" is completed second, then he has the Emeralds to place in the altar. If "Knuckles" is completed first, Knuckles holds onto the Emeralds until Sonic finds the Temples. If "Knuckles" is completed second, Knuckles takes a Warp Ring to the nearest Temple to place the Emerald at the end of the stage.)
Title
Sonic & Knuckles 3D
Expanding on the Level Design:
I haven't played the majority of the Boost games to completion, so I actually don't know what the best Boost levels would be, exactly. Even just stacking together the levels I have played of Boost in Generations/Forces, without menus or anything in-between to interrupt, would be a much more solid overall experience than any of the games on their own.
I haven't played Unleashed to completion, and don't plan to; the game seems like it's conceptually interesting but a bit of a disaster in execution. Simply splitting up the 2 styles in 2 separate campaigns allows each distinct flavor to be enjoyed on its own. Rather than forcing the player to go between the two haphazardly, the player chooses which they want to play.
Boost and Beat-Em-Up, in the same package, but separated. Each is simple/intuitive/easily accessible and shareable with other players. It's easy to pick-up either, but there's a high ceiling for mastery in speed running and finding every secret.
The wide, wacky sea of extended Sonic cast can be easily justified & provide value (in Beat-Em-Up as back-up buddies for Knuckles) while keeping the core focus tight on Sonic & Eggman.
Though Boost should stay limited to 2P/split-screen or 2P/online, there's less need to limit that for Beat Em Up stages. Assuming the engine could handle it, 4 player Beat Em Up would be super fun. Each additional player after 2 doubles the amount of enemies to compensate.