Felt like I missed some tutorials regarding the wall jumping and swimming. Maybe I missed them? And the vines felt very weird to control. I felt like I couldn't get the right combination of keys down to stay on them when I wanted to be.
Neat group of mechanics, though! I think there's room to expand upon them. Felt a bit like early game Portal before you have the Portal Gun. You could add a whole second part where the player has more control over their size changing and make a bunch more puzzles and stages around that.