Depends on whether or not you'd classify Wolfenstein 3D as 'M-rated'... Even for the time, it wasn't very shocking, it's wasn't like I hadn't seen swastika's and Hitler images before. Anyway I probably played that first when I was like 6 years old.
Otherwise, it's Duke Nukem 3D when I was 8.
Neither game damaged me even though I was young...













