The game got really repetitive. I made it into wave 5.
Couple things you could work on: the ladders. They are really broken, you need to stand exactly in the middle of it to be able to climb it.
The sounds of gunshot - it ends too quickly. It needs to fade away, not a straight cut. Also, when you shoot a wall, the sound doesnt even get into a half.
Other than that, nice game, the music was fine.