Games like Zerion 12
Games like Zerion 12 include Aliens: Dark Descent, DG2: Defense Grid 2, Defense Grid: The Awakening, X-Morph: Defense, and Dome Keeper. We matched them by the tags players give Zerion 12 on Steam (Action, Strategy, Tower Defense, Real Time Tactics, and 3D): closest matches first, and among equally close ones the better-known games.
Aliens: Dark Descent
Shared: Strategy · Action · Real Time Tactics
DG2: Defense Grid 2
Shared: Strategy · Action · Tower Defense
Defense Grid: The Awakening
Shared: Strategy · Tower Defense · Sci-fi
X-Morph: Defense
Shared: Strategy · Action · Tower Defense
Dome Keeper
Shared: Action · Tower Defense · Sci-fi
Sanctum 2
Shared: Tower Defense · Strategy · Action
Creeper World 4
Shared: Tower Defense · Real Time Tactics · Strategy
Starship Troopers: Terran Command
Shared: Strategy · Military · Sci-fi
Bloons TD 6
Shared: Strategy · Tower Defense · 3D
Infested Planet
Shared: Strategy · Action · Tower Defense
Taur
Shared: Strategy · Action · Tower Defense
Thronefall
Shared: Strategy · Tower Defense · Action
Space Run
Shared: Strategy · Tower Defense · Action
Orcs Must Die! 3
Shared: Tower Defense · Strategy · Action
SENTRY
Shared: Tower Defense · Strategy · Action
Iron Marines
Shared: Strategy · Action · Sci-fi
Anomaly Warzone Earth
Shared: Strategy · Action · Tower Defense
Orcs Must Die! 2
Shared: Action · Tower Defense · Strategy
FTL: Faster Than Light
Shared: Strategy · Space · Sci-fi
Outpost: Infinity Siege
Shared: Tower Defense · 3D · Strategy
Orcs Must Die!
Shared: Action · Tower Defense · Strategy
Alien Shooter TD
Shared: Strategy · Tower Defense · Action
Door Kickers 2: Task Force North
Shared: Real Time Tactics · Action · Strategy
Starship Troopers: Extermination
Shared: Action · Sci-fi · Aliens