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?

Classic Tower Defense meets space exploration. Build turrets on mining platforms, harvest enemies to build more defenses, and mine Dark Energy to travel the stars. As a sentient AI, you must upgrade your tech, scan planets, and find a new home for humanity before Earth fades away.

Valdis est un hybride dynamique tower defense et third-person shooter en univers sci-fi. Défendez le noyau énergétique d’une station spatiale contre des vagues de zombies, combinez tourelles et éléments, déclenchez des réactions dévastatrices et survivez avec votre fusil à pompe !

A first-person strategy game blending colony building, lane-based battles, tower defense, and action combat.

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.

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.

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.

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.

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.

Design and drop your droids to fight, build, and conquer. Mine resources and outlast the relentless swarm to claim the planet.

On a forgotten world, confront a malevolent machine intelligence. Extract minerals, build factories, power up the railguns, and arm the missile batteries. Defend the Fortress Omega against the alloyed nightmare.

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!

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.

Defend your base by placing towers strategically, forming interconnected systems that depend on one another. Adapt your strategy to different environments and enemy waves, exploiting their weaknesses. In System Status: SuperCritical, resources are scarce and critical failure is always an option.

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.

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.

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.

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.

A sci-fi low-poly tower defense game. Design your defense against waves of aliens using a wide arsenal of different towers.

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.

Endless Tower Survival is a roguelite tower defense survival game where a single tower fights against endless hordes of enemies. Combine weapons and upgrades to create unlimited power tower and survive as long as possible.

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.

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!

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!

Gather your crew. In Solitary Horizons, up to 4 players fight to survive a hostile alien world - scavenging resources, building fortified bases, and deploying intelligent robot companions against waves of relentless threats. In the dark, something is hunting you. Stay together, or die alone.

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!

SOLUM is a floating-island factory sandbox. Extract Sol and automate production across an expanding Island-Network. Build networks, route goods, and keep your islands stable against the pull of a collapsed star.

Mine, defend, and profit across planets. Expand your operation, survive enemy waves, and discover dangerous hidden worlds in this minimalist sci-fi strategy shooter.

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!

Tower Defense Roguelike with Action RPG elements, combining base building, real-time strategy, resource management, and intense top-down combat. Build by day. Defend by night. Explore and survive, if you can.

Build your spaceship, Gargantua. Establish industries, shape the free market, trade between planets, and defend your wealth. A single mistake can collapse supply chains and trigger interstellar economic crises. Remember, war is money.