Pretty easy, but enter as a button? I'm using left hand on WASD, right hand on mouse and have to move one of them to hit enter, it's not the best idea :P
I like the idea of gaining power to defeat the snake, too bad it was so short!
And the startup can use some work, you go through the tutorial for 20s and the suddenly the game starts and you get hit with no warning.
Overall, good job, it's fun to play ^^