Nice little game, but I found it hard to control.
It was a while before I realised that I have infinite double jumps. Originally I was using the friction that game objects initially have to stick the player to the wall and jump up using that :D Constantly pushing up to repeatedly jump higher can be a bit fatiguing, especially at the speed that the game and character moves. Saying that though, I did find myself in level 2 jumping as high as possible to see if any secrets are up at the top, then I found the coin!
The music is nice, and I like how it fits the level, the second level music is a bit darker.
Unfortunately the instruction screen at the start disappears in a couple of seconds, so I never got to read what my trial was about, however, I still found both coins and won the game!
I like how the power up enables to you destroy the spike hazards. And after using it I just kept killing myself to replenish it :D
I did once accidentally activate it when on the instructions page.