Not out of context within this thread, there is ongoing event on /vr/ retro video games board where both skilled and newbies alike make Doom levels with playable areas depicting their beloved anime characters. Doom is easiest game for modding, don't fret to give it a shot if you'd like. Any first timer questions will be answered in retro fps general thread, don't waste your time deciding.
https://desuarchive.org/vr/thread/9890843/#9896579 