Games like APT
Games like APT include Freeman: Guerrilla Warfare, Natural Selection 2, Sanctum 2, SUPERHOT, and KovaaK's. We matched them by the tags players give APT on Steam (Action, Indie, Strategy, and FPS): closest matches first, and among equally close ones the better-known games.

Freeman: Guerrilla Warfare
Shared: Action · Strategy · FPS

Natural Selection 2
Shared: Strategy · Action · FPS

Sanctum 2
Shared: FPS · Action · Strategy

SUPERHOT
Shared: Action · FPS · Indie

KovaaK's
Shared: Action · Indie · FPS

Bright Memory: Infinite
Shared: Action · Indie · FPS

Insurgency
Shared: FPS · Action · Strategy

Total Tank Simulator
Shared: Action · Strategy · Indie

PUBG: BATTLEGROUNDS
Shared: FPS · Action · Strategy

Counter-Strike
Shared: Action · FPS · Strategy

PAYDAY 2
Shared: Action · FPS · Strategy

Counter-Strike: Source
Shared: Action · FPS · Strategy

WARDOGS
Shared: Action · FPS · Indie

Aimlabs
Shared: FPS · Action · Indie

Sanctum
Shared: Strategy · FPS · Action

Hell Let Loose: Vietnam
Shared: Action · Strategy · FPS

Squad
Shared: FPS · Action · Indie

Ravenfield
Shared: FPS · Action · Strategy

ORION: Prelude
Shared: Action · FPS · Indie

Black Mesa
Shared: Action · FPS · Indie

Primal Carnage
Shared: Action · FPS · Indie

Paladins®
Shared: Action · FPS · Strategy

Mount & Blade II: Bannerlord
Shared: Strategy · Action · Indie

Gunfire Reborn
Shared: FPS · Indie · Action