Nice idea for a game. I also got the crash after getting a certain amount of 3-in-a-rows though. It seems trivially easy to just avoid the O's and collect the X's, paying no attention to the tic-tac-toe board. There needs to be some incentive for collecting O's. For example, how about if collecting O's makes you go faster (so you have to collect them) but you need to be careful not to put 3 O's in a line? Just an idea. Well done for making this though!