This game was really well done! It feels very smooth and polished, and the art style is cute and looks really good.

I like the tongue mechanic, it works well and is a cool idea.

For the most part, the level design was challenging, but didn't feel too unfair. However, a few things did make it feel a little unfair (to me at least):

• The hitboxes on the "poison mushrooms" (I guess?) seem way too big. Very often, I find myself dying when I'm standing on a brown mushroom with a purple one next to it, because I move just slightly before I jump and it's so sensitive it kills me. Making those just a bit smaller so that didn't happen would greatly improve the experience for me.
• While jumping works pretty well, it's kinda weird that if you start going left/right in midair, you can't stop. I'm not sure if this was intentional, and if you were going for totally classic/arcade feel, that's fine, but it's kind of frustrating that you can start moving in midair, but you can't just drop down straight after letting go of the left/right button.

Those two things combined made me more and more frustrated as the game got harder, even though the level design was great.

Also, I think it'd be nice to explain the controls in-game. It's kind of weird to have to go to the game page for that. Having some remappable buttons would be awesome, but I understand if you don't want to do that.

All in all, the game is fun! I enjoyed it, but I think the game would be even better if the frustrations above were addressed. Ultimately, it is your game though, so take my feedback (or any) with a grain of salt.