I really should play Beat the Devil, assuming I have time on my hands.
This is just a big coincidence - yesterday I found myself playing Captain Bible.
Destroy the Dome of Lies from within, liberating the poor citizens who’ve been fed CyberLies. Rebute their lies about Christianity with passages from the scripture (that you find in terminals placed all around). Also, battle some robots.
I kinda liked it. It had a specific age group in mind (probably a specific gender, too), and played directly to that demographic. Did I play any more after the third scripture-encounter? Nah. But I’m way past the target demographic, I’m sure. 
An IF author I really enjoy is Eric Eve and he’s christian and his faith subtly shows in his IF works, but without ever feeling preachy.
His friend Jim Aikin is a notorious atheist and wrote a short escape piece on the subject called Heavenly, that is mildly fun and ironic.
And I’m not either of them.
That reminds me; another Christian game I enjoyed was “All Hope Abandon”. There are just too many good things to say about that game.
I did keep thinking about that one, but couldn’t remember the actual title. A good game, certainly.