Hah seem like you know a lot more about DOOM modding than me!
No, the mod i'm talking to is a DOOM-themed mod for OpenXcom Extended. Basically we collected all the OG assets spread around the community into one, single mod.
I could make a Doom style palette for xcom/xp. If you're making custom tiles you don't need to rely on balancing to standard colors that are on built in tiles. Stronger reds, more peachy skin tones, the purple range can be repurposed for something else like ultraviolet. Ill whip up something and post it.
If you're going to do doom stuff it needs Revenants who are fast with strong melee damage, use the high quality doom sound pack for their punch sfx too. And a decently powered accurate ranged attack too with the right sfx. X-P doesn't have Revenants.
I think there needs to be a Cyber too but I don't know if it can be done without squishing it. But remember there is that cyberized Baron style thing from eviternity and realm667 and its head maybe can be replaced by a cyber's shrunk down.
Is Mancubus 2x2 monster possible with a low accuracy fireball burst spread? Id make them 1 radius spread explosions maybe 50ish damage.
My opinion is also among weapons...
Plasma Gun should do about 40ish equivalent damage because its like a battle rifle or machinegun in what it does, its just lightweight and easy to manage (40 ammo per cell makes the most sense, the gun pickup in game gives you 40 cells). Aimed burst 4 shots, Snap Shot burst 4 shots and Auto Shot 8 shots.
Also openxcom doesn't support BFG dymanics but the original alpha (bfg 2701) was a plasma blunderbuss on steroids, and the quake 3 version of it was like a plasma scorcher but less damage (id say bursts of 4 shots with maybe a 5 tile radius spread, make the damage do what you want it to).
Chaingun aimed burst 2 shots, snap burst 4 shots, auto shot 6 shots.
Make sure UAC rocket launcher takes down (tough) enemies in the equivalent number of shots like it should.
Imp fireballs should be piddly and only somewhat accurate (like overall 45-50% chance), remember they do less damage than a single plasma gun shot, but id give them a burst or auto(x3) attack available. Maybe give it good penetration compared to its (25ish) damage so it does chip damage.