Games like 51:22:51
Games like 51:22:51 include Atomic Heart, BONELAB, Half-Life 2, Half-Life: Alyx, and BONEWORKS. We matched them by the tags players give 51:22:51 on Steam (Puzzle, FPS, Action-Adventure, Action, and Psychological): closest matches first, and among equally close ones the better-known games.

Atomic Heart
Shared: FPS · Adventure · Action

BONELAB
Shared: VR · Action · FPS

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

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

BONEWORKS
Shared: VR · Action · Puzzle

SUPERHOT VR
Shared: VR · FPS · Puzzle

VLADiK BRUTAL
Shared: FPS · Action · Puzzle

Cyberpunk 2077
Shared: FPS · Cyberpunk · Sci-fi

Rise of the Tomb Raider™
Shared: Action · Adventure · Action-Adventure

Superliminal
Shared: Puzzle · Psychological · Psychological Horror

Portal 2
Shared: Puzzle · Action-Adventure · Action

RoboCop: Rogue City
Shared: FPS · Action · Cyberpunk

Little Nightmares II
Shared: Puzzle · Adventure · Psychological Horror

Moss VR
Shared: VR · Puzzle · Adventure

High On Life
Shared: FPS · Action-Adventure · Adventure

SIGNALIS
Shared: Psychological Horror · Sci-fi · Puzzle

Inside the Backrooms
Shared: Puzzle · Psychological Horror · Adventure

BioShock Infinite
Shared: Action · FPS · Adventure

Black Mesa
Shared: FPS · Action · Sci-fi

INDUSTRIA
Shared: FPS · Action · Sci-fi

Deus Ex: Human Revolution - Director’s Cut
Shared: FPS · Action · Sci-fi

Tomb Raider Game of the Year
Shared: Action · Adventure · Action-Adventure

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

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