Games like OSIRIS
Games like OSIRIS include DOOM Eternal, DOOM, Black Mesa, Trepang2, and Half-Life 2. We matched them by the tags players give OSIRIS on Steam (Indie, Early Access, Action, Gore, and Violent): closest matches first, and among equally close ones the better-known games.

DOOM Eternal
Shared: Gore · Action · FPS

DOOM
Shared: Action · Gore · FPS

Black Mesa
Shared: Action · FPS · Sci-fi

Trepang2
Shared: Gore · Action · FPS

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

BioShock Infinite
Shared: Action · FPS · Shooter

Ready or Not
Shared: FPS · Shooter · Action

RoboCop: Rogue City
Shared: Action · FPS · Gore

Wolfenstein II: The New Colossus
Shared: Action · Gore · FPS

Bright Memory: Infinite
Shared: Action · Indie · FPS

Serious Sam 4
Shared: Action · Gore · FPS

Bulletstorm: Full Clip Edition
Shared: Action · Gore · Violent

CARRION
Shared: Gore · Action · Indie

Metro Exodus
Shared: FPS · Action · Horror

Call of Duty®: Black Ops III
Shared: Action · FPS · Shooter

Hotline Miami
Shared: Indie · Action · Violent

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

METRO 2033 Redux
Shared: Action · FPS · Horror

My Friend Pedro
Shared: Indie · Action · Gore

Prodeus
Shared: Gore · Action · Indie

METRO Last Light Redux
Shared: Action · FPS · Horror

Resident Evil Village
Shared: Action · Horror · Gore

Wolfenstein: The New Order
Shared: Action · FPS · Gore

Hotline Miami 2: Wrong Number
Shared: Gore · Action · Violent