Top similar games like Astra Defender:

You are in command of the human fleet, searching for asteroids to mine, extract resources and build bases and more ships to defeat aliens invaders. This simple and short action RTS has a full and exciting campaign, and a skirmish mode that allows you to play a different mission on every match.

A classic RTS featuring traditional base-building, resource-driven warfare, PvP, skirmish, and a powerful, easy-to-use Mission Editor. Build your base. Secure the ECO. Conquer the battlefield.

Command distinct factions in a desperate struggle for power and resources in Tempest Rising - a classic RTS set on Earth after a nuclear war.

Metal Mars is a real time strategy game where you race to gather resources and build on mars! This game can be played locally with a shared screen with up to three friends (4 players total). There are also 30 challenges to complete against the CPU!

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?

Build up your fortifications, place your cannons, and fire at the enemy forces! Improve your Battle Haven with powerful upgrades while playing through a story campaign comprised of dozens of scenarios with unique mission types and multiple boss fights! Take to the sky and win!

VR RTS meets shooter: command armies and fight with your own aim on the Andromeda front. Capture building slots, manage 3 resources, and win fair 1v1 and 2v2 battles.

A real-time strategy combat game based on the world of the Line Of Defense. Command a team of four Galactic Command marines in highly classified missions in space and on planets.

Space Gears is a next-generation Strategy set on Mars. Don't fret about micromanaging build orders, or your resources. Set your sights on victory by raising an army of mechs and build up your base in this fluid and fast-paced PvE and PvP strategy game.

Engage in an intense space shooter that you can play in single-player or multiplayer with up to 6 players. Play a variety of different spaceships, each with their own unique stats, components, and playstyles!

Fast-paced space RTS with 10-25 minute matches. Command fleets, conquer systems, or research the Singularity. Simple controls, strategic depth, but no 3-hour commitments required.

Frantic 4-player laser ricocheting top-down shooter. Keep it casual and enjoy the chaos, or master the surprisingly deep mechanics to obliterate your enemies. Duke it out locally in free-for-all or 2v2.

A unique mix of RTS and Action: take control of a powerful combat mech, build your base, raise an army, and fight alongside your forces on the battlefield.

Build spacecrafts and fight with or against your friends! This game offers physics driven gameplay, with a variety of weapons and powerups. Slice your enemies in half with a laser beam, or erase them from existence with a black hole bomb!

Stellarcraft is a sci-fi tower defense adventure: explore alien planets, gather resources, build defenses, and fend off waves of enemies, solo or in 4-player co-op. 🚀

Cyberwinter is an isometric action strategy game. On a distant planet with a harsh climate, you have to fight legions of dangerous monsters for a new home for humanity. Build bases, develop and defend them.

Grey Galactic is a real time strategy game in space where you build up your planets and ships to conquer your enemies. Develop your empire and fleet of spaceships to destroy your enemies and take over the galaxy! Do you have what it takes to become the best Fleet Captain the UFMC has ever seen?

In this massive RTS game, command vast armies fighting for control of entire worlds. Control the forces of Earth, the mechanical AI Substrate, or the enigmatic Post-Human Coalition as you battle across the solar system in single player, cooperative multiplayer, or competitive multiplayer.

Fight for control of a frontier world. Gather resources, build your base, and command your forces in battle. Survive long enough to unleash your ultimate weapon - THE EPIC.

First-person drone combat meets RTS base-building: command historical squads, advance from stone to lasers, and power the outpost’s defenses and superweapon to seal a space-time rupture.

With the shifting gravity on your side, aim your cannons, blast your enemies and enjoy the fireworks. Worbital is a real-time strategic artillery game in space, peppered with a heavy dose of cosmic chaos. The goal: be the last civilization standing!

Halo: Spartan Assault brings the excitement of Halo combat to Steam for the very first time. Battle your way through 30 action-packed missions against the Covenant as you explore the origin of the Spartan Ops program featured in Halo 4. *DirectX feature level 10 required. *

The RTS/FPS phenomenon has moved into space! Build your base on an asteroid, command fleets of starships for epic battles, pilot fighters, mine and trade resources, assemble robots to defend or assault other stations. Take sole command or share the glory as you fight for control of the quadrant.

A strategy where battles are limited only by the boundaries of the notebook! Experience a unique real-time strategy experience where every battle unfolds on the pages of a sketchbook, and all your units and structures are drawn with ink!

Become your teams In-Game Leader and lead your team of 5 agents to victory.

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.

Crossfire: Legion is a real time strategy game featuring tactical action in furious battles across a shattered version of the near future. Raise and customize your army to engage in intense online combat and carve your own path as you rise through the ranks. It’s a new generation of warfare.

Micro Wars is a fast-paced RTS that throws you into the action in short, intense online battles featuring up to 8 players. Tailor your strategy with a variety of commanders and units, build your base, and micro your way to victory. Hone your skills with the campaign, and then climb the ladder ranks!

Stake your claim, command your fleets, and wage epic war in space.

Cubic Annihilation is a fast-paced RTS that demands skill and tactical thinking. Build your own faction by crafting a custom loadout of units, structures, and modifiers, then command cubic armies across land, sea, and air in tight, real-time combat.

Wage war across entire solar systems with massive armies at your command. Annihilate enemy forces with world-shattering TITAN-class units, and demolish planets with massive super weapons!

Build bases, lead an army of robots, and squash brains in this radical hybrid between RTS and third-person shooter. Join a duo of quirky heroes on a mission to save Earth, smash an evil alien corporation, and complete their comic book collection.

Take command of the fleet of starships that is the home to the remnants of your civilization. Manage the limited space of each spacecraft and find the balance between living space, production, defenses, and weapons. Explore the galaxy as you seek refuge and safety from an overwhelming threat.

Pursuit of Power® 2 : The Chaos Dimension is a fast-paced real-time strategy game with pixel art. You assume the role of a powerful Shadow Knight, Stalker, or Mage. Upgrade abilities. Dynamic world events. Manage fortresses. Campaign and skirmish (local or network).

Use ships to attack and destroy enemy space stations in real time.  Navigate through different randomly setup star maps to get to the exit and win.  It's a 2D single player space game that's massively replayable.