I would think Christian oriented games would be fairly easy to make.
For example, you have games like SimCity, where you build a city balancing resources, transportation, population, etc.
You could build an ark, you have to cut down trees, build enclosures, make it x cubits by y cubits, etc. Then you would load animals and supplies, making sure carnivores aren't next to herbivores, rebuilding enclosures if the animals won't fit, etc. Then you could handle being in the ocean, having to clean, feed, water, protect the animals, sending out birds to see if they find land, then navigating to get there and release all the animals.
You could make a game like a "zombie infection" type game, instead its spreading Christianity, and having to handle governments, competing religions, occasional miracles, whatever.