Games like ReSizE
Games like ReSizE include Half-Life 2, Portal, Portal 2, Black Mesa, and Atomic Heart. We matched them by the tags players give ReSizE on Steam (Action, Strategy, Puzzle, Singleplayer, and Sci-fi): closest matches first, and among equally close ones the better-known games.

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

Portal
Shared: Puzzle · Singleplayer · Sci-fi

Portal 2
Shared: Singleplayer · Puzzle · Action

Black Mesa
Shared: Action · FPS · Sci-fi

Atomic Heart
Shared: Action · Singleplayer · FPS

BONEWORKS
Shared: Action · Physics · Singleplayer

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

Titanfall® 2
Shared: Action · FPS · Singleplayer

Half-Life: Opposing Force
Shared: Action · FPS · Singleplayer

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

Hardspace: Shipbreaker
Shared: Sci-fi · Singleplayer · Physics

Halo Infinite
Shared: Action · Singleplayer · FPS

SUPERHOT
Shared: Action · FPS · Singleplayer

BioShock Infinite
Shared: Action · Singleplayer · FPS

STAR WARS™ Republic Commando™
Shared: Action · FPS · Singleplayer

DOOM: The Dark Ages
Shared: Action · Singleplayer · FPS

Bridge Constructor Portal
Shared: Puzzle · Strategy · Singleplayer

RoboCop: Rogue City
Shared: Action · Singleplayer · FPS

DOOM
Shared: Action · FPS · Singleplayer

Aliens: Dark Descent
Shared: Strategy · Action · Sci-fi

Polarity
Shared: Puzzle · Strategy · Action

Ravenfield
Shared: Singleplayer · Action · FPS

STAR WARS™ Battlefront II (Classic, 2005)
Shared: Action · Sci-fi · Singleplayer

DOOM Eternal
Shared: Action · FPS · Singleplayer