This is actually pretty addicting!  The controls feel tight and intuitive, and the difficulty increased at a really comfortable rate.  I also liked the presence of power-ups,  as they gave me a reason to move around and provided subtle changes in the gameplay.  The only issue is that the game does become a bit boring after a while, which could be easily solved with different enemy types or new powerups.  Obviously, those things are hard to do with the limited time frame of a game jam, but I think they would add a lot to the game if you ever decide to add to it.  Overall, well done, and congrats on submitting a finished game!