How many people go on a shooting rampage play a lot of violent video games compared to those who don't? Even then, the number that do are so small that you can't blame video games.
The best way to stop what happened in Colorado is to 1. harsh punishment, painful and fast instead of waiting 30 years in jail before actually killing him. and 2. More open Gun laws, if a few people had guns in that theater, he could have been stopped before the death count got that high. More gun laws will mean only the criminal will have guns, and he feels safer to go on a rampage.