Highscore! This could be even higher, but itgot boring after a while. The OP strategy is standing in the middle, holding right mouse button constantly and mashing the space bar.
Did you notice the difficulty increase while you're playing? I've made the game for only 3 hours so not much time to add more content in the game but I didn't think anyone could reach that high :D
There were more and more enemies, who also became slightly faster, but as every door can hit many enemies, the difficulty at 1000 wasn't much higher than on 200 points.