I'm here because of your post to the playtesting thread:
I really liked the happy / evil style of the game. One mechanic I really liked is the health mechanic in the first two stages. It's actually a bit of a welcome surprise.
I enjoy how there's a little story in there, the UI disintegrates when you're sucked of your happiness etc. It was a bit of an unexpected storyline. It reminds me of 'Little Red Riding Hood'. I suppose that's the flowers part talking.
As for your floatyness from what I could tell it seems as though there's a multiplier on the jump button or it's time based and increases exponentially. That and it feels like the gravity is far too low and the left / right directions aren't sensitive enough in a jump. I fell that's where your 'floatyness' comes from. Addtionally, the collision detection with walls for wall jumps feels very inaccurate. I felt as though I didn't have any confidence in timing when jumping from walls.
You can have a look at my game which is a platformer (my first also) to see how i've configured platform jumping (no wall jumping though, at least not off a flat wall). Admittadly it's not my code in the bare bones (credits are in the game) and I'm using GameMaker 2.0 so there may be some engine differences there. However, I'm familiar with code and have altered a lot of the barebones code I used for the platforming mechanics overall. Perhaps it might give you some kind of 'feel' to change up your code a bit?