The connecting power ups was kind of neat, though I couldn't figure out what the did really (were they just a shield).
Like other people have said, speeding up the game would help it out, as would having either a charge shot or just having the character shoot all the time. Obviously additional powerups would be interesting as well.
One time my WASD controls just sort of stopped working and also at some point connected to an enemy powerup through my regular powerup. But I'm not going to fault a game made in 2 days for having glitches.
Anyway, good job and congrats on finishing!