Nice to see another chapter of this! Certainly a promising sonic-esque platformer that you're building up here, and it seems to get a bit better each time I see it. I'll just give you some play-by-play impressions as I went through:
Level 1: Decent level, basic stuff, very easy, but good to start off and get used to everything. Does feel a bit silly at times though, like how you can be standing right next to a rock wall and hit roll to smash through it: you'd almost expect to have to charge up or build up momentum. Can get health back so easy I practically don't need to think about it. Again, though, fine to be forgiving starting out.
Level 1 Cow Boss: Good variety of attacks, but sometimes it felt really confusing to figure out when you're free to hit him. Had loads of times when I tried to attack him right when he finished an attack, but he'd suddenly transform into a new attack right when I hit him and I get damaged instead.
Level 2 Snow Stage: Nice to see so many new mechanics like rails and see-saws. Can't really get a handle on rails, end up losing speed and coming to a stop, slipping around, reversing, feels awkward. Some nice puzzle sections like where you need to use the seesaw to make a ramp to get up...oh, maybe not and I'm just supposed to wall jump? That's a bit of a letdown. I appreciate the increase in challenge but it just started to get really annoying with so many see-saws and snowballs rolling down: a real uphill battle, pardon the pun. Felt like I was playing those annoying Hoth levels on Super Empire Strikes Back, it's just too much and I end up wanting to facetank through it!
Level 2 Hat Boss: Decent, fun animations, certainly easier to determine when I can attack compared to the first boss, but he was a disappointing one-trick pony.
Level 3 Mirror Stage: What a cool level! Love the whole puzzle element of having to look in the mirror to see invincible platforms and hazards reflected. I wanted more of this! Though, sometimes it was a bit annoying to be speeding along and suddenly you're in a mirror and you hit some spikes in the mirror you couldn't see coming. Speed and these puzzles don't mix well at times I guess.
Level 3 Eye Lasers: Again, I appreciate the increase in difficulty and having a unique race challenge, but I literally cannot beat this. Not only do a lot of the courses feel like annoying trial-and-error, but some courses I do not physically know how to build up enough speed to get away. I feel like maybe I'm missing some sort of hidden tech I'm suppose to learn about how to accelerate or something: maybe this is why I was having trouble with the rails earlier on, maybe I'm missing something. I tried everything though: spamming roll, spamming jumps while rolling, jumping and hitting down into a roll, backtracking to build up a head of steam, nothing works!
Side note: if you jump straight up when next to a wall, I don't think you could wall-cling to it unless you physically move towards the wall. Since this game doesn't do that, the character can feel too clingy.