it wasn't so much the theme as it was, and is, the graphics. I can play horror-style games, but with a game like Doom the horror-style + gameplay is just too intense. I'd love a similar game with a less intense theme.
For example, I can handle Nintendo-style cutesy graphics even if the gameplay is really difficult (Celeste, for one).
I've heard it's pretty bad, or at least the snes version is, but it's one of those games with kind of a cult following. I have no idea about the steam version, though it says it has some improvements. As far as I know this is one of the only non-horrific/grotesque games made on the doom engine.
That's a shame. I mean, it's not so much that I'm all hung up on avoiding 'non-christian' themes. It's more that I don't react well to horror stuff and a lot of the best games have a lot of that (Dark Souls, The Last of Us, Doom). I wish I could just not care about the surface-level skinning, but it affects me nonetheless. At least with horror movies I can cover my eyes or part of the screen!
For example, I can handle Nintendo-style cutesy graphics even if the gameplay is really difficult (Celeste, for one).