Top similar games like Galactic Siege:

A strategic and action-packed base survival game where you mine crystals, build units, and defend your base against waves of UFOs. Defeat enemies, gather resources, and unlock new planets to expand your defenses. Are you ready to conquer the galaxy?

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.

Autothysis is a first-person tower defense game where strategy meets precision. Deploy turrets, manage resources, and fight swarms of insectoid enemies. Target weak points to shatter foes while upgrading defenses to survive escalating waves. Can you withstand the oncoming horde?

Project Astra Dominium is a Tower Defense game with Basebuilding and Automation elements. Build up your base to become a supply hub for Earth's desperately needed materials, gather resources while defending against an unknown alien threat and improve your tower's and AI capabilities.

Build. Defend. Survive. Expand. A sci-fi base-building game on a hostile alien world. Gather resources, build a sprawling high-tech colony, and defend against relentless alien threats—then unlock new planets, new challenges, and the secrets of humanity’s last frontier.

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.

Terminal squad: swarmites is a game with indirect control where you must erect a chain of buildings, which generate resources for construction or the combat units for destruction of an enemy.

Dive into Astronaut Assault, a third-person Sci-Fi tower defense game, and battle against relentless enemy waves in diverse arena settings. Arm yourself with an array of turrets, traps, and gadgets to halt, hinder, and outmaneuver your foes.

Defend your tower for as long as you can from the aliens invading your space! Level up, earn money and new units, and strategically place them in the grid!

This is a sci-fi strategy game featuring a Defense Mode focused on tower defense and an Attack Mode focused on combat. The game includes over 30 different buildings and units, all of which can be upgraded through entry editing to enhance their performance and firepower.

Defend entire planets against hostile invaders in this full 3D tower defense game. Manage resources and space while constructing weapons, defenses, and structures to withstand the destructive onslaught across multiple planets.

Maia is a colony building game set in the not-so-distant future. Your colonists make planetfall on a hostile world and you must ensure their survival and their safety, constructing their off-world habitat from almost nothing and sheltering them from a dangerous, often deadly environment.

An open-ended factory management game with RTS and tower defense elements.

Be the ultimate CEO and military strategist in this genre fusion of strategy and business management. Create your own company, hire employees, research weapon technology, and take control of units on the battlefield to defend the moon against an alien invasion. Aliens down, profits up!

Astro Industry Wars is a lighthearted take on the RTS genre featuring distinct unit types, base building, economic production chains, and customizable unit rosters.

TAVU is a PvE RTS game with a tactical combat system. Build your bases and defend them against waves of enemy attacks. Upgrade your units and destroy enemy bases to gain new territories and resources.

Escape From The Red Planet simplifies resource management, tower defence, and first-person mechanics into a singular arcade experience. On the latest mission to Mars, the Orion III crash-landed. With Martian attacks looming, Houston most definitely has a problem!

Wonder Defense: Chapter Earth is a strategy game based on Earth and Aliens in which you act as a General to accomplish survive and move to Mars.

INTERGALACTICORP. is a sci-fi rogue-lite tower defense game where you take on the role of an operator-bot, charged with conducting an intergalactic mining operation. Will you thrive as an efficient miner in this alien environment, or succumb to the dangers that lurk in the depths of space?

Hostile Mars is a factory-building game focused on combat! Explore an open world and discover new tech to unlock powerful weapons and structures. Create efficient supply chains using delivery bots. Salvage destroyed enemies for resources. Design your base to withstand increasing waves of enemies!

Armoured Onslaught is a fast paced Top-Down Shooter and Tower Defence hybrid. You will need to make use of both strategy and skill as you fight your way through near endless hordes of deadly foes.

TEP the destroyer is a single player tower defense game where you will face alien monsters and ships in ground and space battles! Your strategy will decide the fate of your people in a sci-fi environment of varying difficulties!

Gear up and get going! Defend your outposts from waves of alien enemies with your mech. Build and upgrade your base, protecting the extraction of the mysterious planetary system’s rich resources!

Control a Nanite body from a space station to gather Nanite resources on Earth, seized by a rogue AI. Build and fortify your dropbase with turrets and defenses, fight waves of robotic enemies, and collect Nanites for extraction, balancing fast FPS combat with strategic tower placement.

By managing your tower during the day you prepare yourself for the dangers of the night, the king depends on you to dominate this territory. Will you be able to survive 30 days in this distant land?

The ultimate space capital ship combat compendium is the evolution of hard core space combat sims. The only game of its kind currently in existence.

Tower Defense with resource- and base management! Waves of enemy robots with special abilities, shield and armor! Mining, refining and production for building and repairing! Environmental hazards and the best: the Orbital strike!

Play a sci-fi turn-based strategy game while an AI threat the humanity. A VR experience allowing to discover the famous Listenbourg.

Lose yourself in an indie solo-dev. treasure that harkens back to arcade classics! All while thumping along to killer retro-inspired beats by Ovani sound. Embark on an epic tower defense adventure against awe-inspiring machine monstrosities, made by a devoted gamer for devoted gamers.

Oxygen Not Included is a space-colony simulation game. Deep inside an alien space rock your industrious crew will need to master science, overcome strange new lifeforms, and harness incredible space tech to survive, and possibly, thrive.

Build and defend your base to mine starlight crystals in this roguelike co-op tower defense! Carve paths, build defenses, and upgrade your operation as 1-4 players battle escalating waves of hostile threats across a procedurally generated galaxy.

Explore the Solar System. Mine and drop asteroids. Colonize and terraform. Lead the space race and compete with other corporations on your way to profit. Watch the expansion of human race over the centuries. Then go beyond and conquer the galaxy!

A unique 3D tower defense game set on randomly generated planets! Place towers to defend against 360-degree attacks, protect mining outposts, and survive intense meteor waves. Earn resources, and face endless replayability with dynamic challenges every playthrough!

It's the year 5781 -- and you have been chosen to build and lead a space station in a wild corner of the galaxy! Attract visitors and explore hundreds of planets to fund your station.

Guide pioneering settlers among Venusian clouds in this space colonisation city builder. Grow food, collect energy, mine resources, balance buoyancy and weight to stay afloat in the treacherous Venusian atmosphere, and build a self-sufficient colony while navigating storms and acidic clouds.