There's one character who uses the word "G-dd-mm-t" in every sentence.
The goal of the game is to SHOOT GOD! Multiple times. While there are endings that involve you not killing god, the message that is stamped into your head constantly is "go shoot god."
The main character who isn't the player is known as the archangel (Remember, in Christianity, Judaism and Islam we are taught Archangels are god's messengers). He tells you what to do and gives a weapon.
Now, at this point of the description, you know the kid is going to assume this is a very good guy, and your friend.
Then he starts to say shoot god. But he says it in interesting ways. "Purify the diluted god" and such. He also stresses that this is how to save the world.
Also, something Common Sense does not have badges for, the imagery is very grotesque. Not violent, there's not really blood or anything, but it's certainly disturbing, in fact, I'm 16 and the image on the spine of the game case creeps me out. Characters are distorted humans, some with their heads lodged in their stomached. Everyone's flesh is an ugly brown. One character, if hit, says "Yes, I should just die. DIE DIE DIE." Another character, a big, meaty guy, ends up burying himself, and his body is decaying and shriveled in the ground yet waste up you see him, and he lives. He groans in pain should you hit him. Another recurring character(s) are the littles, winged infants with black holes for their eyes and mouth. It's explained that the gun your character wields shoots the babies into the enemy, the babies expand and both explode and die.