Games like Gun Metal
Games like Gun Metal include Vanquish, STAR WARS™ Battlefront II (Classic, 2005), Titanfall® 2, Half-Life 2, and STAR WARS™ Battlefront™ II. We matched them by the tags players give Gun Metal on Steam (Action, Mechs, Robots, Third-Person Shooter, and Shooter): closest matches first, and among equally close ones the better-known games.

Vanquish
Shared: Action · Third-Person Shooter · Sci-fi

STAR WARS™ Battlefront II (Classic, 2005)
Shared: Action · Shooter · Third-Person Shooter

Titanfall® 2
Shared: Mechs · Action · Shooter

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

STAR WARS™ Battlefront™ II
Shared: Shooter · Action · Third-Person Shooter

DAEMON X MACHINA
Shared: Action · Mechs · Robots

ARMORED CORE™ VI FIRES OF RUBICON™
Shared: Mechs · Action · Robots

HELLDIVERS™ 2
Shared: Third-Person Shooter · Action · Shooter

Lost Planet™: Extreme Condition
Shared: Action · Mechs · Third-Person Shooter

Mecha BREAK
Shared: Mechs · Robots · Action

Black Mesa
Shared: Action · Sci-fi · Shooter

PRAGMATA
Shared: Action · Third-Person Shooter · Sci-fi

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

Binary Domain
Shared: Action · Third-Person Shooter · Robots

EARTH DEFENSE FORCE 6
Shared: Action · Third-Person Shooter · Shooter

Warhammer 40,000: Space Marine - Anniversary Edition
Shared: Action · Third-Person Shooter · Sci-fi

EARTH DEFENSE FORCE 5
Shared: Action · Third-Person Shooter · Mechs

EARTH DEFENSE FORCE 4.1 The Shadow of New Despair
Shared: Action · Third-Person Shooter · Mechs

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

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

Front Mission Evolved
Shared: Action · Mechs · Third-Person Shooter

Grand Theft Auto V Legacy
Shared: Action · Shooter · Third-Person Shooter

Metal Wolf Chaos XD
Shared: Action · Mechs · Third-Person Shooter

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