Wits & Wagers

Hello, I recently purchased "Defense Grid" from Steam. It will frequently glitch during a game - basically it will force zoom, and any menu I try to bring up, it will act as if the cursor is being run up and down repeatedly. I've tried pausing the game and coming back to it, going into submenus, etc and seeing if it will work. Whenever it happens, which is frequently, I am forced to stop the game and restart. Often when I stop the game it will also crash completely. I have been trying to play and just force quitting every 10 minutes or so when it glitches. But now, it is glitching every 2 or 3 minutes. Please advise.