With two Sonic games coming out this year, Sega starts off strong with Sonic Mania, essentially a love letter to the Genesis titles made by fan-game creator Christian Whitehead and using his Retro Engine. Basically, this game is what Sonic 4 Part 1 and 2, which were average games at best, should be.
The first thing I have to say is the level design is superb. They provide a nice balance between platforming and speed, and even with levels that were simply reused themes, such as Green Hill Zone, have some sort of twist. Controls are also nice and responsive (as far as gameplay is concerned) and works well with either single or duo Joy-Con play. The graphics also receive an upgrade from the Genesis. In fact, I could go as far as to say it's more like a 32x, maybe Saturn, game, and the animation is pretty fluid and bouncy. In the special stages, it goes into an Emerald Stage, which is chasing an UFO to catch get the Emerald, goes into a Saturn like style, which keeps use with the classic aesthetic the game has.
If there are some issues I have, they're small, but they are noticeable. First of all, this is the Switch version I'm reviewing, and these problems seem to be exclusive for the platform. Also, from what research I've did, the port to Switch was done by Tantalus Media, who were responsible for many licensed games, though they do port jobs such as Legend of Zelda Twilight Princess HD, Zombi (which is basically Zombi U for PS4, Xbox One, and PC), and the soon to be release Rime for Switch, so I can't blame the main devs themselves, and I can only imagine the company will do a better job with Switch games in the future. Anyway, one of these two issues is that the special stages, which I'm sure isn't that demanding on the Switch, does drop frames. They're not big dips like 60 fps all the way to 15 fps. It just drops down to the 50s for a second and that's it, and that's if you experience it. Another, more noticeable issue is that the Home and Screenshot buttons have a delay. Yeah, you heard that right. These two buttons have a delay on the Nintendo Switch, and sometimes, they don't even work. Again, they're not gamebreaking bugs, easily overlooked even, but it's kind of disappointing that they exist. They should be fixed whenever they release a patch though.
Simply put, this game is a love letter to the classic games of the Genesis, and whatever system you want it for, it's a must have, and even with the Switch version's problems, it's still the version I recommend getting, if you have one. It's simply that much of a blast, even without Blast Processing.
UPDATE: Due to a recent patch that was FINALLY delivered. Not only did they fix the Home button issue, but they added a separate button for Super Form, which is now X instead of tapping jump twice, so no accidental transformations.