While both game has an enormous amount of blood in it, and should NEVER be play be children or people with impressionable mind, I believe Grand Theft Auto 3 is more violent.
Why? Because Grand Theft Auto 3 has an extreme realism that is rarely found in any video game today. The game is so realistic, that you could easily learn how to become a true criminal just by playing it alone.
Thrill Kill may have a tone of more blood than Grand Theft Auto 3, but Thrill Kill doesn't have the realism to back it up.
Which do you think is more violent? Thrill Kill or Grand Theft Auto 3? Or do you have your own game to name?
P.S. I would have put this in the non-Mario place, but practically nobody goes there!
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A World Without Nintendo Is A World Without Video Games.
Nintendo, Born To Play.