The true ending was particularly spectacular, wearing its influences and heart on its sleeve with pride and controlling incredibly tightly. Its sense of presentation is stellar, and is doing some of the things I've always wanted to do with this engine. Basically, thank you mirumiru for my life.
Honourable mention to Egg World for kickin' several kinds of ass, and Highly Responsive To Hedgehogs for being... highly responsive to controls, and good even in the face of being an entirely unrelated game put in SRB2. I never felt like any of the times I failed in that was the game's fault, which is a great thing to say about a challenging experience. Finely tuned to heckie and back, honestly.
Actually, props to all the Emerald stages. The only one I wouldn't replay for fun would probably have to be SONIGURI; I had some serious difficulty with that even after the forced instruction manual. My main issue was that there wasn't any reliable way to avoid the boss' attacks; at that point it basically became a war of attrition to pump as many missiles into it before I died. This was kind of compounded by an unfortunate fact about the control scheme - shooting any weapon stops you dead in your tracks (yes, I know about the dash to de-lock, but it still disrupts flow and forces me to press a button I don't feel like I should except to cheat the system). I'm not sure how much of my issues are with the mechanics of the original game or whether it's a consequence of the SRBification process, but either way it's a shame, because I really loved the enemies and the way they forced you to move. If there wasn't any movement lock after attacking (at least with the normal laser; the homing missile and giant laser make sense to limit), I could see myself having a lot more fun with this. It's still a great technical accomplishment, but it's let down by one fundamental design decision.
I don't really have anything specific to write about most of the normal levels, so I'll talk about a general, repeating issue I had. They were quite enjoyable, but most (VAda's Pipes of Green, Lat`'s and SAMMY_SWAG's Roasted Ravine, knuxnumbers' Twilight Grove, Sunlit Caverns by someone whose name escapes me, and Glaber's Sapphire Frost being the most prominent exceptions, all of which I thought were exemplary, and Propulsion Peaks by Inferno Drag, which uses slopes well but is let down by having zero sense of flow outside of that and basically being a life and token farm) clearly had some difficulties deciding where and when slopes should be used. And I don't blame y'alls! They're literally a gamechanger, and there are few published maps to provide style guidelines through experience. What should probably be considered is the direct impact of putting a slope somewhere. Sure, the environment is a little more tilted and it looks better, but that has MAJOR implications for physics. The player's going to end up jumping at an angle, physics are going to be resistant... it's a gimmick, and it's one that requires a little more thought than "put it everywhere". The original SUGOI wasn't much better at this, though, so don't sweat it; at risk of making a terrible pun, it's a learning curve.
Deleted Domain's levels actually had a higher standard when it came to slope usage in general, so if you can get 80 emblems that might be an interesting thing to pay attention to. It's good that those levels were salvaged for future generations.
Also, speaking of Deleted Domain; I hate you, Salt, that you still left in what was originally in the gallery in its place. :P
EDIT: Polluted Polis REALLY should've been called Pollutopolis, not gonna lie. That took me WAY out of it, heh. It was an alright level, but not capitalising on the naming choice physically hurt me, aaaaa