One laser. Build a machine of mirrors, splitters and lenses that burns every step of the path. Light gets tired: every enemy it passes through drains it, so where you split and where you strike is the whole game. A tower defense where you engineer the damage. When it slips mid-wave, grab a mirror.

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About This Game

One laser. Build the machine that makes it lethal.

Lethal Geometry is a tower defense with no towers. You get a laser and a budget, and you route the beam with mirrors, splitters and lenses until it covers the path the enemies walk. The beam is where the damage is. Where it goes is up to you.

Light gets tired

Every enemy the beam passes through soaks up part of its power. Drones thin it. Armored hulls drink most of it and shield whoever marches behind them. A bare mirror carries the loss on, and only lenses and upgrades win it back. So where you split the beam and where you strike a column is the whole game: hit it from the rear and the escort melts first, hit it head-on and you waste the beam on the shield.

When it slips, grab a mirror

Build, flip and sell even in the middle of a wave. Click a mirror and the beam swings to another part of the map, straight after the group that just turned the corner.

They fight back

  • Saboteurs knock the mirrors and splitters they pass out of line. Build close to the path for short routes, or further away for safety.

  • Reflectors throw a head-on beam away. Catch them from behind or the side.

  • Jammers swallow a whole branch of the beam.

  • The Warden scrambles every mirror around it each time it loses a quarter of its health.

Draft a different beam every run

Between waves, draft one upgrade that changes how light behaves: afterburn, arc chains, hot mirrors that add power with every bounce, walls that reflect, splitters that waste less energy. 24 cards in all, and the Lab unlocks most of them as you play.

Built for replays

  • 10 handcrafted maps in three sectors, each with its own optical problem: blocks in the beam's way, a wall with two narrow gaps, a hall with a fixed splitter and walls that reflect, a finale with two emitters.

  • Intensity: ten steps of tougher waves on every map, for a higher score.

  • Endless on any map you have won.

  • Restart with the same draft or reshuffle it. Play at 1x, 2x, 4x or 10x.

  • Win or lose, a run pays lumens for the score it made. Spend them in the Lab on new cards, loadouts that trade one strength for another, and a few Workshop perks, then stack mutators for more score.

Good to know

  • Mouse and keyboard. There is no controller support.

  • Windows only. The game is in English.

  • 39 milestones to earn in the game.

AI Generated Content Disclosure

The developers describe how their game uses AI Generated Content like this:

Lethal Geometry's written content and level design were made with generative AI assistance: the in-game text, the upgrade and milestone descriptions, the map hints, the layout and waves of the maps, and this store page.

Nothing you see or hear is generated by an AI model. The board, the interface and the icons are drawn by the game's own code, so the build contains no image files, and every sound effect is synthesised by a script from mathematical waveforms. Nothing is generated while you play: there is no AI model in the game and no calls out to one.
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System Requirements

    Minimum:
    • OS: Windows 10 64-bit
    • Processor: Dual-core 2.0 GHz
    • Memory: 4 GB RAM
    • Graphics: OpenGL 3.3 compatible graphics, integrated GPUs included
    • Storage: 200 MB available space
    • Sound Card: Any
    • Additional Notes: Mouse and keyboard required.
    Recommended:
    • OS: Windows 11 64-bit
    • Processor: Quad-core 2.5 GHz
    • Memory: 8 GB RAM
    • Graphics: Any dedicated GPU with OpenGL 3.3
    • Storage: 200 MB available space
    • Sound Card: Any
    • Additional Notes: Mouse and keyboard required.
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