It's looking nice, plays really well. One criticism is that occasionally I'd not see spikes coming because they camouflage pretty well against the clouds. Maybe that's part of the challenge though, idk...
Also, it might be nice if the big green tutorial text appeared slightly before the player appeared, or if there was a long straight section at the start of the level to give you a chance to read. I failed the first level a couple times since I was reading then fumbling to find the Z key.