This is a really nice game, possibly my favourite so far. I'm surprised it hasn't had more ratings. You might draw more attention with a gif for a main screenshot - take a look at gifcam.
I found the jumping quite difficult at first, but once you get the bubble and double jump it gets a bit easier. I very much like the health indicator design, when you get hit, no clutter. The music and SFX are good. Great atmosphere for a little game. It all fits together so well.