Wow, one of the best games I've played. It's real interesting to choose the pinball arena for a wave based game. The combination of planning where to drop each ball, using a power up, paying attention at both upper and bottom parts of the screen and actually playing pinball is quite perfect.
My only complaint would be that I felt like the level design and physics made it difficult for the balls to drop down, it took quite some time before I could use the flippers.
That was a really impressive entry !