Pretty simple game but I must admit, I found it quite hard and enjoyable. Paying attention to your current colour, the colour of the tiles around you and the location of the gems really puts your brain to work.
I realise this was for a game jam but it would have been nice if you fixed some of the issues before submitting it to the portal. I found a couple obvious issues that should be simple fixes:
1) There is no collision detection to prevent the user from leaving the screen.
2) The game doesn't actually end when your health reaches 0, you just can't play any more. You should add a "game over" screen when the health reaches 0.
I like the concept of the game though. It was a lot more challenging than I expected, assuming I tried to keep moving rather than plan my route in advance. It might be an idea to set some kind of timer so that the user can't remain in the same position for too long, that way it would add to the challenge. Alternatively, maybe the user should always be moving, like in Snake.
With a bit of polish, I reckon this could be quite a fun little puzzle game.