Players will have to build walls, turrets and mobile armies to defend against two wildly different factions of invaders, each requiring very different strategies to overcome.

Over the course of a 23-mission branching campaign, players will unlock new technologies, units and upgrades in order to turn the alien tide, as well as uncover gruelling Survival and Endless challenges for each map. With the odds stacked against them, players can recruit a buddy and tackle the entire game in online co-op, or face down the 44 enemy types solo.

Unlike most tower defense games, Colony Siege allows players to build their fortifications and traps almost anywhere on the battlefield. Walls can be used to funnel enemies into kill-zones and mobile units controlled in traditional RTS fashion can intercept more aggressive foes. It’s a fresh challenge for fans of both regular strategy games and more structured tower defense.

Command your units in battle. Can you survive the enemy onslaught?

Colony Siege is available on Steam Early Access for $19.99/£15.49/€16.79, and will last for about 3 months. The final version of the game is due out by the end of the year.

“Colony Siege currently has the first 60% of the campaign unlocked, including multiple game modes for each mission and full co-op support. We have made a large number of changes and improvements based on our closed beta tests, so we feel that the current state of the game has a high degree of polish and stability.”

Key Features:

• A non-linear 23 mission campaign (14 in Early Access), playable solo or in co-op online.
• Lead from the front, upgrade your command ship and turn the tide with new powers.
• Hybrid strategy; lead a mobile army to complement your mazes of towers & walls.
• Two wildly different enemy forces: swarming alien Xenos and the more human Riven.
• Fight for bragging rights on the global leaderboard, tallying up your total campaign score.
• Spend your bounty from completed missions on permanent new tech upgrades.

Colony Siege is is in development for PC, PS4, Xbox One and Nintendo Switch, coming to Early Access on Steam this summer for $19.95, with a final release planned for later this year.