Not exactly ultra-violence, but quite a shock anyway. SWAT4.
You spend missions after missions throwing flashbangs, asking people to surrender, shooting them when they try to shoot (or in my case, shooting them first with beanbags rounds/taser and then asking them to surrender) and handcuffing everyone. It's a SWAT simulator, no place for story or drama.
Then you've got one of the most difficult mission in a bank with well-trained, heavily armed and armored enemies. And then you get a far easier mission with a crazy sect that's about to commit mass suicide. There are more bad guys but they're not as well trained and they've got no protection. And then
You enter the cave of the building, and find the graves of the children they "sent to heaven" first.
Totally unexpected, and quite shocking.