Hello! Welcome to Feedback Quest 5! It's nice to meet you! My name's Hythrain. I'm part of the FQ team and a hobbystreamer. I'm writing this review live after having played your game.
I find the concept of this game interesting, though right now I do feel parts of it need a lot of work. Hopefully my feedback will give some indications.
The first issue I ran across was how unresponsive jumping could be at times. Usually, jumping was okay. However, there were times where I'd press jump and either get a weak jump that led me to my death or I didn't jump at all. Given how important being able to jump is to a platformer, this is the first thing that should be dealt with. Whether in the middle of the platform or on an edge, the player should be able to jump. Speaking of jumping, if you're running across a wall and you jump over and over, the height gained isn't always the max height despite holding the jump button in full.
The next issue was the wind blowing you back when you're running over the jaws. Not only is this wind excessively powerful if you stop moving, it works well beyond the limits of area. Meanwhile, if you jump before going over the jaws you can skip half of it. I also had an issue when I got to the area with three sets of jaws all together where I was being affected by multiple winds at once.
What I would recommend is keeping the wind active at all times but it only affects the player once they're in the jaw area. In addition, if the player is blown off the jaws they should just stop immediately instead of being sent flying back. Making these changes would fix every issue I saw with this mechanic.
Next, sliding along the wall. While it's an interesting idea to make sliding on the wall trigger the wind up, I can also see this being very limiting or, even worse, annoying players. In some places, the player can kill themselves if they accidentally slide on a wall and get pushed up into spikes or some other obstacle (this happened to me at the demo's end, where I slide on the wall briefly while getting the 11th strawberry and wind pushed me up into the constricting area). Instead, I'd say disconnect the wind from sliding and instead just make those winds exist all the time (and any challenges for berries in them should be about getting it the first time. You miss? You gotta start the screen over). You could then use sliding down walls as a mechanic for getting around when going down and would work well with the axe the player gets at the very end.
Another issue is the sliding and the saliva. When you slide on the saliva, it makes you slide VERY far. If you end up colliding with a wall and then try to jump, you'll just have a bad time. Similarly, if the saliva is on a set of jaws or the end of the jaws, you'll have a bad time as you can't get across. Attempting to slide will push you back, jumping won't work and you lose your momentum from running on the saliva. What I would recommend to fix all of this is give the slide a set movement distance. The player slides, they move a set amount. This amount is higher when on saliva. This way, you can directly control how far the player can slide.
The last part I want to comment on from the game itself was the constricting area. You clearly know how to make animated walls closing and opening, as you have this happening for the jaws. This needs to happen with the constricting area too. It looks awful right now with the snapping open and close.
I also want to cover one general is in regards to controls. A good platformer should have tight controls, aka responsive and easy to judge. Jumping can still be floaty like how you're doing it, so long as movement is quick, jumping is immediate and the player can easily predict how things will go. If I'm right, you're using a physics engine for this rather than manual inputs. While I know the physics engine can help with stuff, I would recommend trying to avoid it for a 2D platformer. It makes controls less tight and makes artificial difficulty for the player.
That's all from me. If you want the VOD, I can share it when it's uploaded to my YouTube.