Top similar games like Crystal Nexus: Alien Siege:

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.

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!

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.

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!

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.

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.

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.

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.

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.

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

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!

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 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?

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!

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?

"SYNCHRONIZERS: UNDEAD MARINES" blends high-quality Three-Lane Tower Defense with Reverse Tower Defense gameplay. Command your units in a thrilling narrative reminiscent of a StarCraft and Plants Vs. Zombies fusion! Your choices will forge the path to victory—or defeat.

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!

Galactic Overlord is a rogue-lite deck-builder.  Travel the galaxy, hone your deck, find strange and powerful artifacts, and defeat the rebels!  Balance your deck carefully to maintain the favor you have with the different factions!

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!

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.

Astra Sentinel is a real-time strategy game in which you must defend planetary systems from endless hordes of aliens. Reconquer planets, build on their surface and prepare to counterattack. Will you be able to recover the control of the galaxy?

Tau Cubis is a mazing tower defense game set in colorful sci-fi landscapes. Use your strategic skills to overcome numerous challenges and advance through the leaderboards.

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!

You wake up in a gloomy room. Become the test subject of a shady software program that feeds on Tower Defense - Roguelike - Deckbuilder simulations.

A sci-fi tower defense game. Build an army of towers to stop waves of a lured alien species called Zektid's.

Year 2425, humanity colonized the exoplanet named SACH-041840. But then, in the 55th year "they" came; No one knows who or what controls them, but what is known is that if they reach the colony proper, it will be annihilated. It is up to you to bring the WRECKONING upon them!

Build towers and learn abilities to defend against swarms of hundreds of on-screen hostile alien creatures. Choose between sets of randomized upgrades that both upgrade you and the alien swarm. From enormous explosions to far-reaching flamethrowers, no two games are the same.

Civilization was born from a chaotic star system and has been constantly tested in its development, from ancient civilizations to occupying the entire galaxy, which is long and dangerous.

A city-building strategy game with colony survival elements. After an alien invasion drained Earth’s resources, rogue machines roam the ruins. Gather resources, lead your colonists, rebuild from scratch, and fight for survival. Survive. Rebuild. Resist.

It’s a defense game where you create your own strategy, grow your units, and defend against enemies.