A rare moment of seriousface from me, but I digress. Seeing as it's the last OLDC for this version of SRB2, I may as well contribute with some comments 'an votes.
Single Player Levels
Green Canyon Zone: An interesting level, quite enjoyable to. The water skipping gimmick was quite well executed, especially at the end (Although, on one occasion I missed the end sign post entirely, whoops.)
However, there's also a point where I feel there was a lack of direction and I went the wrong way.
6/10
Aquatic Labyrinth Zone, Act 2: I have to say, this was a good, fun and challenging map. Although, I felt that the air bubbles were difficult to see in the green colourmap and as a result I drowned a few times through what I felt was no fault of me own. Also, I got the impression that this stage was perhaps a little to long, what with it taking me 10 minutes to clear on my first play through. However, that's just my own blundering, so it's a tad unfair to remove points for that. (Besides, it's GOOD level design, even if it is long.)
Aside from that though, this was a well designed stage with several sprawling pathways, a very challenging design and with some nice visuals to boot, not to mention a fair few clever gimmicks.
9/10
Hidden Sanctuary Zone, Act 2: My first thought was "Meh.", although, as I played through it a second time I found myself enjoying it much more due to the alternate paths. For example, in my first play through I had passed underneath the bridges and had just mistaken them for scenery, but on my second play through I had found them to be alternate paths. I like.
Although, on the negative side of things. The stage was pretty and all, but aside from a few pretty scenery moments (E.G., the gargoyles and the light up torches) I didn't notice many stage gimmicks that keep things innovative gameplay wise. By all means, it's a good map, but it never caught my attention.
7/10
Glaber Base 5: I have to ask, why oh why is there a section specifically for Sally?
Anyway, after playing through the level with Sally and with the normal trio, there are a some significant problems that bring the enjoyment factor of this level down, such as, daft level design. To be more specific, the awful crushers at the start. They are simply to difficult, cheap even.
On top of that, there are a few questionable enemy choices. I can understand the Minus', seeing as they are your own creation, same applies for the Drilla Killers. But the old Crawlas and Eggmobile was just... What. A downgrade really isn't idea. (Speaking of the Eggmobile, shouldn't that have been at the end of the level, instead of the mid-point?)
Anyway, I have to give you credit for being original, but often these original ideas brought the map down due to poor execution or just plain being a bad idea.
6/10
Cosmic Galaxy: Forceskin, alright, I can see why that is there. The map is a little easy with Knuckles or Tails. What with flying/Climbing and all. But I digress, the theme was quite an interesting one and the visuals caught my eye (then threatened to give me a seizure, but that's another point entirely).
But, pretty looks aside, there is not much going for this stage, the laser walls are absurd to get past without jumping around them, which I think is unintended and the Zero Gravity gimmick was interesting, but because I mistook the first one for a pit, jumped and flew across the ceiling, I did the same on the second Zero Gravity section and fell to my death. A rather cheap kill that could only have been avoided if I knew what was coming up already.
4/10
Flooded Forest Zone: I was originally a little reserved, due to 2D stages often not working very well in SRB2. But I quite enjoyed it to be honest. Although, I do think you over used the spikes + blue springs, also, Water Section was quite uninteresting. The boss fight at the end was a nice and unexpected touch though.
5/10
Factory Farce Zone, Act 1: I see someone's been playing Sonic CD. Wacky Workbench olol
Anyway, the bouncing floor was both unexpected and very good fun, not only that but it was applied to the level quite well with some good use of FOFs and the harmful ceiling, also the music was quite nice to, very fitting to the theme.
On the topic of visuals, I would have looked at it poorly because of it was, for the most part, a grey+black factory stage. Thankfully, the orange ceilings and the multi-colored flashing floors covered for that.
On a more negative side, the level was over to quickly and I felt it was a tad rushed. The hidden room near the exit making me think this, due to it being totally unfinished and empty. Also, you made the emerald token a little easy to reach in my opinion.
7/10
Mill Citadel Zone, Act 2: YES, on so many levels.
It's fun, challenging without being frustrating and original, mind you, original in comparison to the majority of SRB2 wads. The Flour Mill idea is running old in my opinion. That aside, I was impressed by the way you created fake rotations (which you proceeded you use, a lot, perhaps a little to much) and crammed as many different gimmicks into the stage as possible, including a take on the Deep Sea Zone slide, which is always a plus.
Also, I found both emerald tokens, hooray for secret hunting. Better get used to it, there's gonna be a lot of emblems to find in SRB2 2.0 :P
9/10
Greenery Pass Zone, Act 2: Very nifty, original music and a sunset theme, I wonder if act 3 will be at night. Also, original scenery is used in this stage (namely, the new rocks)
However, despite this, I felt this stage was pretty and pleasant to the eye, but rather boring to play due to it being seriously easy.
6/10
Match Levels
Diamondus Battle: A bit reminiscent of Sapphire Falls, isn't it? It's nearly identical in parts (Such as the center design, with the river feeding into a lake) But that aside, it felt like a 2.0 stage (or at least, what I assume they are like) because of the non-symmetrical layout and I think that the weapon rings chosen for this map are better than the ones in the current Sapphire Falls, Auto Bomb > Auto Infinity.
6/10
Aerial Match Zone 2: I heard a few complaints from some Sonic players regarding this stage and how the lower half was much better than the upper floor. But I have to disagree as a Knuckles player, the vantage point is fantastic for ninja-Knux gliding strikes from above :p
Although I rather enjoyed this stage, it was an original design
That aside, I think there were a few to many ring monitors around for a stage that size, it was quite easy for me to stock up on more rings than I will need.
7/10
CTF Levels
Geometric Void Zone: This stage was... Interesting, much like Nimbus Ruins in the current level pack, it was interesting and good fun. Mutli-layered and designed so that all 3 characters had a use.
Although, on the server I played this map in, there were some lag problems and as a result we died, a lot. A LOT. It was tolerable though despite this, which I think says it all, the level was still enjoyable despite near constant deaths.
Although, I think this map would have worked much much better over LAN, to create a lag free environment where the deaths are only your fault and not the distance from the hosts.
8/10
Diamondus CTF2: Far FAR to similar to Sapphire Falls to be a coincidence, it nearly copies this stage sector for sector at parts. That aside, it's, eh. Really, really, similar to Sapphire Falls =/
By all means, Sapphire Falls is a nice CTF stage, but so, very, very, similar.
3/10
Illuminated City Zone: Getting the flag is easy, without a doubt to easy, what with the current version of SRB2 having very little ways to defend your base, however, the stage is small enough to make up for that as the flag carriers are never far away (and yes, the flag WILL be taken)
Although, because of all the different routes in this small hectic map and how the attacks generally make a bee-line down the central path, it's quite easy to return to your base.
Also, for defending, there's an exploit that the flag carriers can abuse, by standing on the elevator floor, it is only possible to shoot them from one route and the flag carrier is able to easily escape back down the elevator shaft.
Despite this, I did enjoy the map but it was quite flawed.
6/10
Circuit Levels
Submerged Cavern Zone: Overall, quite small and with a curious gimmick, why is a player able to lower the water with a button? as far as I could tell, no water only made that section harder for all players involved (easier in fact for anyone who happens to be ahead of you, because they have to do the dry version one less time) so no one ever pressed the button, not to mention that you lost valuable seconds jumping on it.
6/10
Star Reactor: Quite epic. Quite epic indeed, it did turn into a thok fest but to be honest that;s what all race maps are. Anyway, this was an enjoyable, long, race track. With several routes that are all roughly equal (I assume though, if I had more time, there would likely be an ideal route which in time would be the only one that people take.)
Although, the point with the death pit was unexpected on my first run through and because of the hoop floating in mid-air, I careened right into it as Sonic mistaking it for a jump.
8/10