The Living Room Arena

The idea

A mixed-reality wave-defence game where the room is load-bearing, not decoration. Invaders breach your real walls; your real furniture is the only cover, Strikers suppress and burn through it, and ammunition only restocks from caches that spawn on your actual surfaces. Every mechanic is chosen to fail the test "would this still work in an empty box?" — so the scan has to matter.

What we built

Three enemy types, each punishing one habit: a floor melee that counters standing still, a ranged Striker that takes cover behind your furniture, and a ceiling Wisp that ignores floor cover. Health ratchets down a segment per wave so turtling never buys the run. A validation gate reads any room and gives a readable reason — too little floor, ceiling too low, too few walls — rather than a broken match.

How it was engineered

The key decision is that the room is an interface, not an SDK type: every system reads an engine-agnostic room snapshot, and exactly one file in the repo touches Meta's types. That is why the whole game builds, plays and balances on a desktop with no headset, why the room analysis is covered by fast headless tests, and why a Meta SDK change has a one-file blast radius. Scenes are generated from C# rather than hand-authored, so a broken scene is fixed by re-running a command.

Status

The room model, combat, enemies, wave director, the mixed-reality rig, passthrough and furniture occlusion, tactical AI and the designed UI are all built. It is verified by 169 headless tests and by an unattended soak run that drives the real desktop build through whole matches — and by screenshotting every screen, since tests say nothing about whether a frame is legible. Not yet run on a headset: the Quest path compiles and builds, but on-device validation and colocated co-op are still ahead.