This happens when I play for a longer time and it first happened during the prison escape chapter. Suddenly the game does not react to keyboard keys any more, not for choosing a character, not for choosing a weapon. Stopping the game, with the mouse obviously, and starting again does not help. restarting computer does however.

So far I had this twice, both in the same chapter. Another 'common' problem is that Left Alt Mouse does not do anything from time to time (turning left or right). However when it gets stuck changing character makes it work again. I've had some other quirks as well, like the A button that suddenly acted as a Q button (I'm on an Azerty keyboard), but this could be resolved by quitting and starting again.

Anyway, it seems that there is a keyboard problem somewhere...