Great game, but has one critical bug.

Pretty darn good, but it's got some issues. I too experienced the bug where the bullets all get mashed down to go no further than your buildings, and the game grinds to a halt. For me, this happend twice on level 30.

My strategy is to build two overlapping layers of turrets all the way across, and put reflective walls all the way across at the very highest row. I don't even have to shoot at that point, and just buy upgrades or maintain my walls.

It would be really nice if we could SELL turrets and buildings, so we can recoup some of our investment. If you do another versioin maybe? :)