let me preface that i'm only one person and experiences may vary before i get into a full review. i really like the menu, the art on it is nice and i like the little hat! the bird is cute, the art in general is cute (love the pug so much :3). the tutorial serves its purpose quite well, giving demonstrations on every possible mechanic and source of confusion a player may have. the mechanics are fun and creative, it's enjoyable as a platformer.
i don't have much criticism to give here, one softlock i found was getting stuck right before the gear and between the lollypop when it taught me to inflate in the tutorial because i got confused on where to go. i think this was more a me thing but it could be nice to have arrow indicators on where to go next in the tutorial. i still think the tutorial is quite helpful though and it's really good!
when i hit the roof or when using the propeller the pug instantly falls down, this may be intended but i think it could be better if the pug maybe slowly descended. i got a bit annoyed getting stuck from hitting the ceiling and falling on the spikes, i think that also may be a personal issue though, it's just a bit tight of a squeeze.
checkpoints may be nice for each gear, of course you may need to expand the levels a little though if you did that.
the hidden spikes in level 2 may not be visible enough, maybe an outline could be good? i died from it initially and was a bit surprised.
more in the background could be nice if you had time.
overall this is a really solid game! i liked it and as a fan of platformers i'd actually like to see more levels from this game, good job :)