I've had about four times this game has frozen on me. I'm not sure if its just the blast lag or what, but I'll be in the process of putting a bomb down, and then the screen freezes and i have to force quit the application because I can't do anything. I've been lucky enough to join back in before the game was over, but I'm worried one of these times I won't. Dunno how to suggest a solution since I'm sure lag is involved, but yeah. Major problem.
Actually lag thing happend to me too, except it was more like the lottery lag thing, but it seems to have cleared up by now. Try it now and see if things have improved.