Exhibit 13

Grimwood Museum. Gallery 13. Midnight.

You're the new night guard, and there's only one rule. Learn the gallery as it should be. If anything is different, turn back at once. If nothing is different, carry on through.

Each right call moves the clock on an hour. One wrong call and it's midnight again.

The gallery holds Lady Grimwood's portrait, a suit of armour, a sarcophagus, a longcase clock with a raven on top, the Grimwood Skull in its glass case, a Roman bust and a prize pumpkin. Most nights, most of it stays still.

• 35 anomalies.** Some you'll see from the door. Some are a painting's eyes, or a number on a clock face. Some you can only hear.

• A catalogue** of everything you've spotted, and everything you've missed.

• Tonight's Shift:** the same galleries for every guard tonight. Keep your streak going.
• Graveyard Shift:** twelve hours, with subtler changes. It unlocks after your first escape.
• - A shift takes 5–10 minutes. **Best with headphones:** the sound is placed in 3D.

Controls:** W A S D or the arrow keys to walk. Mouse to look (click to capture it), or ← → to turn. **T** turns around, **Shift** runs, **Esc** pauses. On phones and tablets, your left thumb walks, your right thumb looks, and ↺ turns around. Controllers are supported.

Made in three.js with custom shaders and spatial Web Audio. Everything you see and hear is generated in code; the game is about 170 KB.

Spooky rather than gory. There's one mild jump scare.

AI disclosure:code written with AI assistance. No AI-generated graphics or sound; all of it is generated in code.