Games like DOOM 3
Games like DOOM 3 include DOOM, DOOM 3, Half-Life 2, Black Mesa, and Left 4 Dead 2. We matched them by the tags players give DOOM 3 on Steam (Horror, Action, FPS, Sci-fi, and Dark): closest matches first, and among equally close ones the better-known games.

DOOM
Shared: FPS · Action · Gore

DOOM 3
Shared: Horror · FPS · Action

Half-Life 2
Shared: Action · FPS · Sci-fi

Black Mesa
Shared: FPS · Action · Sci-fi

Left 4 Dead 2
Shared: FPS · Action · Horror

Resident Evil Village
Shared: Horror · Action · First-Person

DOOM Eternal
Shared: Action · FPS · Gore

F.E.A.R.
Shared: Horror · Action · FPS

Half-Life
Shared: FPS · Sci-fi · Action

Call of Duty®: Black Ops III
Shared: FPS · Action · First-Person

Half-Life: Alyx
Shared: FPS · Horror · Action

BioShock™ Remastered
Shared: FPS · Horror · Action

BioShock™
Shared: FPS · Action · Horror

METRO 2033 Redux
Shared: FPS · Horror · Action

Aliens vs. Predator™
Shared: Action · FPS · Horror

BioShock Infinite
Shared: Action · FPS · First-Person

Resident Evil 7 Biohazard
Shared: Horror · First-Person · Singleplayer

Outlast
Shared: Horror · First-Person · Gore

DOOM: The Dark Ages
Shared: Action · FPS · Sci-fi

Resident Evil Requiem
Shared: Horror · Action · FPS

The Darkness II
Shared: Action · FPS · Horror

Half-Life: Opposing Force
Shared: Action · FPS · Sci-fi

Halo: The Master Chief Collection
Shared: FPS · Sci-fi · Classic

METRO Last Light Redux
Shared: FPS · Action · Horror