Nice game but...
I have too many issues with this game to make it fun.
First: Jumping problems. As stated, even though I push Up, she doesn't jump, typically resulting in tripping on a ledge.
Second: Deadly randomizing. There were several times where the generated cave resulted in me getting killed by simply making one mistake. This alone made it no fun.
Third: Mushroom cave spikes. The floor spike balls a too big. If I wasn't dieing by tripping too much, I was typically jumping onto the spike balls. They require to be near pixle perfect to get over and that's just bad design. Too early typically had me jump onto the back spike while too late threw me headlong into the front spike. Shave them down a bit and it would be better.
Last: A combo of the darkness/dust wall and the dropping ceiling. I'm sorry, when I have to spam the Down key just to stay ahead, that make this impossible to play. Unless I'm mistaken, you can NOT outrun the wall normally. You HAVE to you the Slide Boost just to stay ahead, if not at speed with the chasing doom. The fact you put that as a hint(Tip! Did you notice that you get a speed boost when you initially slide?)means it is bad game play.
The Slide boost should be how the player recovers from trips, not basic mode of transport. The wall should move at the same speed at the player and they only have three, maybe four trips before being killed by the wall. On the flip side, Slide Boosts should allow the player to outrun the wall if they are too close and try to get some breathing room. Fix it to be like that and I'm sure people will have more fun with this game.