The closest things I could think of for Doom scifi would be Hacx (d2 total conversion) or Marathon (that had dual wielding guns + team ai iirc)? I wouldn't know if they're similar at all, having not played either. Corridor 7 acts more like Blake Stone probably than Doom. Rebel Moon I think used 3d hardware so no. There's the Terminator series but I can't go anywhere with that. I'm out of ideas.
Witchhaven reminds me of Heretic, but that's by looking at screenshots. I wonder if Strife would connect to something. Some many Doom-like stuff in fps concept only - it'd be like me comparing World of Goo to Lemmings, which counts to me as puzzle category and that's the end of practical similar.
You could also try looking at gamefaqs "related" suggestions - sometimes I find new stuff that way. Although I think I have a more liberal idea of similar.
ehh.. One more then since I haven't been doing much around here anymore.
Brain Dead 13 vs Dragon's Lair
- Hand-drawn animated cartoon (decent Don Bluth-like style)
- Choose from 4 directions or action key
- Nearly every scene can result in quick death
- Not much time to decide correct response, although you can mash buttons early
- Same rooms play in normal or mirror-flipped fashion
- Some rooms offer split path choices
- Gruesome animated deaths
- Talkie
- Swordplay
- Spooky castle
- Multi-plats, iOS higher def remake
- Kill, avoid monsters
- Final super boss battle
edit:
me wrote:Although I think I have a more liberal idea of similar.
I'll just give examples of what fits my idea of "if you like this, try looking at this also" mentality:
. Thousand Arms (ps1) - Lunar (ps1) [anime style, humour style, voice actor delivery]
. Legend of Zelda (nes) - Neutopia (pce) [familiar mechanics, theme]
. Secret of Mana (snes) - Secret of Evermore (snes) [same company, similar style]
. Ultima (c64) - Questron (c64) [general theme]
. Blackthorne (snes) - Flashback (snes) [gameplay mechanics]
. Metal Gear: Ghost Babel (gbc) - Perfect Dark Zero (gbc) [somewhat similar theme]
. Nosferatu (snes) - Castlevania (*) [theme vein]
. Darkstone (pc) - Diablo (pc) [gameplay mechanics]
. Gradius (nes) - R-Type (nes) [gameplay mechanics]
. Ys 3 (snes) - Sorcerian (pc) [gameplay mechanics, theme - although Sorcerian is party-based]
. Streets of Rage (md) - Final Fight (snes) [theme, gameplay mechanics]