I plan to introduce my child slowly, at their own pace, to both movies and games. The first few times I plan to sit with them, explain anything they don't understand, put things into perspective, and answer any of their questions. Once they understand that the violence is purely comedic, or designed to show how bad these things would be if they happened in real life, then I'll let them play/watch other things.
Even then, extremely violent or sadistic stuff (ie. manhunt, aka murder porn) I'll keep them away from until they;re at least 15. And their play will be monitored when they do. Honestly, it's not about denying kids things. It's about being a parent and making sure the video games don't start to become their own twisted reality. They're images on a screen, an escape, a form of entertainment. Nothing more.