This question was based off of the Cybershell and LS Mark debate. In my opinion, I think that both games are good but what do you think?
I can see positive qualities in both games, but personally I prefer SA2 is better.
Reasons being Heroes has more slippery movement, it really kills it for me, Power Characters tend to be the best as they are slow enough to allow more room to breath without falling off of ledges like sonic, and fast enough to not be boring. Flight feels shallow, Thundershooting foes is really nice but that's about it for me, they are super slow for one thing, they can barely fly so it makes platforming with them feel very strict, like if you move a inch to far you can't make it to the next platform, like you have to go to the absolute tip and stills feels like you pushing it.
It's still a fine game but I find the movement to be a glaring issues, and enemies with massive HP tend to get annoying later on, I understand that's what power characters are for to give them purpose other then making them fan floating fodder, but after awhile is just feels mindless and boring, they should have balanced how much HP foes would have or make the enemy encounter more complex, like a mini boss to keep it engaging, at least that's what I would like to see.
SA2 has it's own issues, Like Treasure Hunting stages, that I've gotten a little more soft on, I used to hate them, but with experience and the fact the hint monitors lowering your score is so small you can still get and A rank anyways makes them feel less annoying, but still worse then SA1 because of the radar, I would understand if the stages were small and compact but no, some stages get really big or for rouge a timer for a level, so having this nerfed radar feels really pointless when the scale of some stages should really make up for the radar being open, and timed stuff is always stressful so not knowing a Emerald is right next to you is frustrating if it cost you in anyway.
Speed stage are linear but given how the gameplay breaks up so much It makes sense because it suits speed much more and they are more fun then challenging, at least to me that's how they came off.
Mech Stages I have kind of a soft spot for, mostly Eggman because I love Eggman the stages do feel like they can go on for a bit to long at times though but it feels like they fleshed his stages out the most compared to tails, who feels like he gets shortest stage by comparison, not bad, but Tails didn't do much for me, like at least Eggman's final stage gimmick was pretty fun and creative use for simple it was.
But if we have to choose what's best, Objectively It's Sonic Unleashed of course, Sonic can boost, he has green eyes, snazzy shoes, and most importantly he eats ice cream in the game what more could you possibly want?