Machine Guard Corps is a free browser sci-fi lane defense auto-battler. Your command base sits on the left, an alien hive on the right - summon five kinds of machine units, buy permanent evolutions, upgrade your Command Tower and turret, and use three active skills to hold the line. The hive is not a fixed wave script: it manages its own energy, upgrades itself, and eventually sends boss after boss, then double-boss rounds. About ~130 KB, no install, no account.
Want a faster, timed arcade game instead? Try Black Cat on a Hot Tin Roof.
Summon machines, evolve units, and defend your base from an adaptive alien hive. From Machine Guard Corps by Mars723 (MIT). About ~130 KB, downloads once when you press Play.
Number keys 1-5 summon units, or use the on-screen buttons. Works with mouse/touch alone.
Machine Guard Corps is a free browser sci-fi lane-defense auto-battler you can play with no account and no install. Press Play to load the game in a same-origin iframe, then press Start Defense on its title screen and hold your command base against an adaptive alien hive.
Key features
- 5 machine unit lines - Robot Infantry, Mech Dogs, Attack Drones, Big Fat Bots, and Railgun Walkers - summoned with number keys 1-5 or the on-screen buttons, each with 2 permanent Scrap-bought evolution paths (10 evolutions in all).
- 4 upgrade trees - Command Tower, Base Turret, Coolant Banks, and Combat Firmware - each with 5 levels, bought with Scrap using keys Z, X, C, and V or the on-screen buttons.
- 3 active skills on independent cooldowns - Missile Strike, EMP Pulse, and Repair Swarm - to swing tough fights, each improved by the Command Tower and Coolant Banks trees.
- A heat system - units that attack build heat and shut down for 2 seconds at 100 heat, which Coolant Banks upgrades help mitigate.
- Both fortresses, your base and the alien hive, auto-repair after 8 seconds without taking damage, at a speed tied to the Command Tower upgrade.
The alien hive adapts on its own
The alien hive is not a fixed wave script. It manages its own Alien Energy, upgrades itself over time, and triggers emergency invulnerability shields at 50% and 15% of its core HP, which also refill its energy.
Boss roster and win condition
The hive eventually sends named bosses. Its 6-boss roster runs Hive Siege Core, Broodmaw Crusher, Void Prism Tyrant, Carapace Sovereign, Dreadspire Artillery, and Star-Eater Monarch, and once that roster is exhausted, rounds escalate to double-boss fights. You win by reducing the hive's core HP to zero before your base falls.
Privacy and saved data
Everything runs on your device. Nothing leaves it except the initial page and the roughly 130 KB of game files loaded from this site - there is no server backend, and the game keeps no scores, progress, or unlocks between sessions.
For more free browser games, open the games hub.
Frequently Asked Questions
What is Machine Guard Corps?
A free browser sci-fi lane defense auto-battler: defend your command base from an adaptive alien hive by summoning machine units, buying evolutions, upgrading your base, and using active skills.
How do I control it?
Number keys 1-5 summon units, Q/W/E trigger skills, Z/X/C/V buy upgrades, and Cmd/Ctrl+1-0 buy evolutions - or click the on-screen buttons for every action, so mouse/touch alone works too.
What is the goal?
Reduce the alien hive's core HP to zero. You lose if your command base HP reaches zero first. The hive sends progressively stronger named bosses over time, then double-boss rounds if the fight runs long.
Is progress saved?
This build is session-only. There is no save data - closing the tab resets the game.
How big is the download?
About ~130 KB of HTML, JavaScript, and CSS after you press Play. The browser caches it for later visits on the same device.
Does it work on a phone?
Yes - every action (summon, skills, upgrades, evolutions) has an on-screen button, so it is fully playable with touch alone.
Is this open source?
Yes. Adapted from Machine Guard Corps by Mars723, under the MIT license. This site build adds noindex on the engine page and ships LICENSE plus CREDITS next to the engine.