Having speed be your HP was a very smart choice since you don't have that much control over where you end up going a lot of the time. It sort of has the same problem as Breakout when you only have one enemy left. The collisions are also very small, making hitting things more difficult than you would first expect. Giving the player some other way to use speed to improve their odds of hitting an enemy (like a small AoE burst or homing attack) might be a nice addition to give a little more control to the player. The core is quite fun, but seems like a matter of polish and details to me at this point. Great work for 48 hours.