Single-player games like Galactic Siege
Below are 8 single-player Steam games similar to Galactic Siege, ranked by player overlap. Every pick carries Steam's Single-player category, so multiplayer-only titles or always-online games don't sneak in. imho.run pulls the category data from Steam directly — Single-player here matches what the store labels.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like Galactic Siege page.
Ranked picks
- 1
Mars or Die!
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Action and Strategy with Galactic Siege.
Control two characters simultaneously! Survive, gather, collect upgrades, fight all sizes of one-eyed Martians, build defensible outposts and conquer Mars, in this glorious mix between roguelite and tower defense.
- 2
Wall World Strategy
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Strategy with Galactic Siege.
Build and lead a colony on the surface of an endless Wall. Manage resources and your people, develop new technologies, defend against relentless zyrex attacks, and send robo-spiders on risky expeditions. Keep the colony from collapsing – in Wall World, it's easy to fall.
- 3
Don't Mind the Robots
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Action and Strategy with Galactic Siege.
Build deadly mazes and outsmart a rogue AI in this strategic tower defense game. Adapt your defenses, use aiming parameters to your advantage, and activate powerful perks to survive increasingly complex waves of incoming robots.
- 4
Cosmic Robots
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Action and Strategy with Galactic Siege.
Defend your planet from waves of robot invaders! Build powerful turrets, upgrade your defenses, and command robot units to fight drones, tanks, and massive bosses. Then send your own forces to attack the enemy planet in this action-packed sci-fi tower defense game.
- 5
Calyx
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Strategy with Galactic Siege.
A strategy game with a new kind of enemy, Calyx puts you in charge of a space mining outpost, locked in battle against powerful plant-aliens. Build your base, gather resources, assemble your forces, and take on the Calyx. With only an out-of-date AI for company, can you survive?
- 6
The Alters
Single-player alternative to Galactic Siege — playable solo, no multiplayer required.
Explore an emotional sci-fi game with a unique blend of survival, adventure, and base-building elements. Help Jan Dolski, the sole survivor of an ill-fated space expedition, create alternative versions of himself to escape a hostile planet and tackle personal turmoils with this unconventional crew.
- 7
SYMMETRY
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Strategy and Indie with Galactic Siege.
A research spaceship reaches an abandoned planet. Nothing is what it seems here and the situation quickly slips out of control. Can the crew manage to survive and get back home?
- 8
Dark Moon
Single-player alternative to Galactic Siege — playable solo, no multiplayer required. Shares Strategy and Indie with Galactic Siege.
Dark Moon is a survival strategy game where in order to survive you must avoid the Sun’s scorching rays and embrace the darkness. Gather resources, upgrade your mobile base, make tough moral decisions, but most importantly - don’t go into the light!