Probably the only one but I was enjoying the game until my mask failed and there were none to replace it with. Starting the level over and over is just the surest way to get me to quit any game. No matter how many I kill none have a useable gas mask for me, so I die, restart, get pissed, and waste hours of time. Not fun, stupid, not necessary. So much for what I thought was a great game. The filters are a pain, and stupid too, but I get those. Not having masks despite EVERYONE having one is like I said.