Nah, making a christian game would be potentially offending to christians who don't like games, christians who don't like others' view of their beliefs, people of different beliefs, or people who simply dislike christians.
If a game must be made, make it a game where every major religion is included, and as many stereotypes are being thrown around as possible! Like a King of Fighters clone. Jesus could be in it, trying to make everyone stop fighting, and when they don't he gets himself nailed to a piece of wood! Buddha, who after overpowering his opponent sits under a tree and falls asleep! Mohammed, crawls out of his cave and fights in the name of god before blowing himself to pieces! The Pope could be in it, maybe even some Wiccan witches even though that's not a "real religion". And an atheist who believes himself superior to everyone else, then realizes that EVERYONE'S belief is wrong, including his own, and then... his head.. explodes!
Eh. I'm trying too hard... I don't actually know anything about religion. It's hard to be offensive when you don't know what's offensive and what's not...
But a game like that HAS to have a Trekkie, too.