1. Stardust Speedway - The presentation here is off the charts. Both music tracks make me absolutely giddy, and the transition to Act 2 was like HYPE. AS. FUCK. Unlike most act transitions, Stardust Speedway uses a fade out, which works to suddenly blindside the player with the overwhelming visuals of Act 2. Act 1 is full of fun interactions lifted from Marble Garden, and I like them a lot more here. Also really like the speed tube mechanic where you have to direct Sonic around. Act 2 feels a bit short - perhaps to give the player more time to deal with the boss - and I would appreciated another minute or so. In any case, Metal Sonic is Metal Sonic - likely the most elaborate and well-presented fight in the game. Just all-around amazing.
2. Studiopolis - Holy visual overload. This level bombards the player with interactions, callbacks, and two incredible songs. Love the Heavy Gunner fight for its spectacle, and the Egg Weather Report has some fun details with the chicken weather reporter on the screen. Being the first original stage shown, I have to believe Studiopolis received the most dev time just due to how much is packed into it. It's nonstop fun. And dat act transition. Go big or go home.
3. Metallic Madness - I played Sonic CD when it released on 360/PS3, and really have no notable memories of this zone aside from the shrinking mechanic. That said, Mania's version blew me away. The music's energy is cranked up to 11, and the stage packs in some great gimmicks (shrinking, moving to the background, rotating behind walls). Really enjoy both bosses here, with the gatcha machine being one of the game's highlights. So much better than the original it's not even funny.
4. Titanic Monarch - For the first time when playing a Sonic game I actually felt an oppressive atmosphere with this zone. Tee/Falk did an outstanding job making the music sound foreboding and epic, but still keeping a distinct style. This zone features some of the most elaborate Rube Goldberg-esque setups in the game. S3&K's gravity orb gimmick from the bonus stages make an unexpected comeback here, and flinging Sonic around feels amazing. I also enjoy the setup for Act 2 with the nonlinear sections. Just a great level for me. Also, the one-two punch of Metallic Madness into Titanic Monarch utterly obliterates the endgame of any other classic Sonic game in terms of level design. They're so good.
5. Press Garden - I absolutely didn't know what to think of this zone when I got to it. The name isn't especially descriptive, and it took me a bit to realize the zone was a giant printing press for propaganda posters. That said, the bouncy conveyors are loads of fun, and Act 2's ice mechanic is very original and entertaining. Speaking of Act 2, I think it was obvious to most that Ice Cap didn't have a chance of returning, so seeing that snow start to fall after beating the mini boss was great. Act 2 has bar none one of my favorite environments in the game, with cherry blossoms in the foreground, and an icy river and huge trees and lanterns in the back. Music is also pretty groovy here. A great original effort by the team.
6. Lava Reef - Act 1 here feels much improved over the already-solid original, with some notable additions like the Metallic Madness giant walker things. And Act 2...hoo boy. That guitar feeds my soul. Just spectacular atmosphere with this one. The highs here aren't insanely high, but both acts together make for one of the most consistently enjoyable in the game. Just a really smooth and fun ride.
7. Chemical Plant - A bit torn here concerning Act 1, which condenses both acts of the original into its own remix. While I enjoy classic Chemical Plant, Act 1 here lifts a ton of stuff wholesale without adding much new. Still enjoyable, but not too exciting. As far as I'm concerned, Act 2 is where Sonic Mania as a whole really gets going. Wacky Workbench's bouncing mechanic is redeemed by actual intuitive level design, and the song remix is awesome. This is the first huge taste of Mania's subversions, and it works flawlessly. Act 2 is easily one of the best in the game...oh, and Mean Bean Machine. I fucking suck at these kinds of games, so the low difficulty is appreciated. It's still fun for me even on the fourth or fifth run, so that's cool. Too cheeky.
8. Hydrocity - This zone subverts the traditional structure for classic zones. Instead of Act 1 remixing the original, with Act 2 adding new ideas, Hydrocity does the opposite. Act 1 sees new gimmicks in the form of ridable boats and Aqua Lake's bubbles, and I think it should be noted that both of these gimmicks are pretty slow-paced. You might think they belong in Act 2 to better follow the formula, but it would be jarring to go from a faster Act 1 into a slower Act 2. Instead, Hydrocity gives you the newer-but-slower stuff up front, then let's you cut loose with the classic stage's patented Jesus-inspired ludicrous speed in Act 2. I also really appreciate how the Act 2 song remix stays close to the original, but comes off as higher impact with some added layers. A really good level overall that might be sold short occasionally. Just want to also mention that Act 1's boss is a fantastic moment that ties gameplay and comedy together super well. It's genius.
9. Flying Battery - I like this stage a lot, but didn't feel it added a ton of new stuff. Act 1 stays close to the original, and Act 2 is Wing Fortress redux. It's an enjoyable stage, though. The stormy atmosphere in Act 2 was effective for me, and you reach hypersonic speeds near the end. The spider boss is probably my least favorite in the game due to some wonky collision with his bumper, but it at least has an interesting concept. A solid zone that executes well, even if new ideas aren't as prominent as in stages like Chemical Plant and Hydrocity.
10. Oil Ocean - I had a weird experience with this one. Had no clue the zone was in the game, so when ”Oil Ocean" popped up on the screen I was like ”eh". Didn't hate the Sonic 2 original, but it wasn't my favorite, either. Then I found a fire shield, paused for a second, and thought ”...huh.". After grabbing the fire shield I was plunged into the titular Oil Ocean and lit the place up. I don't think the level design is amazing here, but hauling ass while igniting everything in sight with some pretty satisfying flame sprites is super fun. Act 2 goes for a Sandopolis Act 2 gimmick which works pretty well. I will say that both bosses together likely make for my least favorite paring in the game; the mini boss can crush you without warning, and the main boss demands a good bit of patience since rings can't be recovered if they fall into the oil. Still, an enjoyable stage once you figure out the tricks.
11. Mirage Saloon - I'm insanely torn on this one and it sucks. I'm just not that big on Sky Chase, so Act 1, while still enjoyable, was a bit flat for me. Act 2 though...wew lad. So many fun gimmicks like the guns and water containers that make navigation a blast. Act 2 felt very short to me, though, so that compounded with my issues with Act 1 to knock the zone down overall. Love the main boss, but the mini boss is a bit tedious (I couldn't figure out how to hit him when he's moving between foreground and background). With a longer Act 2 and a different, more traditional Act 1 (for Sonic/Tails) this would have been top 5 for me, easy.
12. Green Hill - Just really basic. I mean, it's Green Hill. The music isn't my favorite in the game, and while Act 2 spruces things up a bit, it's all a bit restrained to keep up with the heavier hitters. A good first level, but not much more for me.