Top similar games like Crystal Nexus: Alien Siege:

Rise of Mutant Swarms is a strategy survival tower-defense game where you defend the base against waves of evolving mutant enemies. Place and upgrade turrets, adapt to enemy abilities, and make critical decisions as the pressure rises with every wave.

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?

Join our machine legion to conquer the world.

A sci-fi Tower Defense game. Strategize to destroy waves of rogue robots and assist the powerful turrets with player controlled drone. Build and collect resources and help evacuate your crew from the alien planet.

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.

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.

Scrap Wars: TD is a Post-Apocalyptic Tower Defence game where strategy meets chaos! Build and Upgrade powerful Towers, Customize their Strengths, and Defend your Base against relentless waves of Enemy Vehicles across three unique Scenarios or Battle for as long as you can in Endless Mode!

Employ lethal turrets, traps, and gadgets to defend against an onslaught of evolving creeps! Step into a twisted, hyper 3D, mind bending realm. Upgrade and adapt your defenses. Become a master maze crafter. Collect bizarre artifacts. Rush creeps for lucrative rewards, and succumb to greed!

A sci-fi roomscale VR Tower Defense game. Strategize to destroy waves of rogue robots and assist the powerful turrets with a handheld drone. Build and collect resources and help evacuate your crew from the alien planet.

Hold a mining outpost on an alien world while thousands of insects pour through the rock tunnels like a flood. Place towers on the high ground, aim their firing arcs, and spend the biomass from every run, won or lost, on upgrades that let you hold a little longer next time.

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

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.

Galactic Garrison is a sci-fi, turn-based tower defense game where you defend your base from relentless alien waves on Mars. Deploy soldiers, build barricades, and upgrade defenses to withstand attacks. Earn powerful reward cards to gain strategic advantages and outmaneuver your enemies.

Step into the arena with IDUN: Prologue, a thrilling slice of our full-length defense RTS where real-time strategy meets rogue-lite chaos. Fight your way through unique mission objectives with overwhelming swarms of enemies.

Step into a chicken-themed tower-defense roguelike where you build and upgrade your coop, think up strategies during the day, and hope to survive when night falls. Wild predators lurk in the dark, ready to tear down your defenses! COTS is action, strategy, collectible cards…and of course, CHICKENS!

Mecharise is a strategy and tower defense game that combines elements of base building, resource management, and wave-based combat against hostile aliens. Pilot a mecha as you colonize new worlds and defend your base against enemy attacks.

A real-time strategy MOBA with deck-building and poker mechanics. Draw your hand, summon unique heroes, and fight for dominance in intense PvP battles.

You believed tower defense is only about building towers? That's not quite right – because AIRA VR is not like other tower defense games in virtual reality. Once the battle starts you find yourself in the midst of the fight!

AT THE LIMITS OF EARTH, AT THE EXTREMITY OF HEAVEN. A REAL-TIME STRATEGY NIGHTMARE.

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 !

Run an off-world mining operation on hostile alien worlds. Set up automated turrets, defend the drill against tens of thousands of flying insects, and extract with the haul before your perimeter is overwhelmed. High risk, high reward retro extraction tower defense.

Lead the Mobile Infantry in this RTS game set in the Starship Troopers film universe. Balance your army composition with a diverse set of unit types, overcome line-of-sight and line-of-fire challenges through tactical positioning, and use special abilities to smash the Arachnid hordes!

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!

Sphere Invasion is Sci-Fi Tower Defence. Build your own road and defend it with 7 unique towers.

A defense RTS where you can move turrets at will. Extract resources, upgrade technology, and defend against enemy swarms in a gripping space campaign. Hold the line, set up your turrets, and brace for screen-filling hordes!

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?

Battlefleet Gothic: Armada is the RTS videogame adaptation of Games Workshop’s classic tabletop game, pitting the Chaos, Imperium, Eldar, and Orks against each other in visceral space-battles.

Taur is an action-strategy sci-fi game. Control the Prime Cannon and unlock all of its powerful weapons and abilities. Build turrets, droids, aircraft and more as you fight to protect the homeworld of the Tauron droids against a relentless invasion. Will your Taur stand against the Imperion warmachine?

Power the Unknown is a strategy game where you build a base on an unexplored planet and defend it from swarms of hostile bugs. Mine resources and generate enough energy to power your ever-growing base.

Slam your towers down and conquer endless maps of enemies in this roguelike tower defense game. Level up, earn loot, unlock powerful upgrades and create unstoppable towers!

Volition's classic is back. Descent: FreeSpace is the quintessential old school space shooter. With a deep story, great graphics and engaging battles against fighters to capital ships it keeps you moving. Breakout that flight stick and enroll with the Grand Terran Alliance today.

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!

SENTRY is an action-defense first person shooter where you defend your spaceship against invading aliens. Plot an escape route through hostile space and battle the enemy across your vessel with the support of traps, turrets and environmental destruction.

An isometric sci-fi RTS of fleet command and orbital industry. Mine asteroids, grow a station from a single command core, research new technology and design your own ships module by module, then wage war across 84 branching missions, survival runs and online battles.