Echowell

Explore a dark 3D facility by revealing its geometry with sonar pulses.

Echowell is a keyboard-controlled exploration game built around active sonar. The facility is almost completely dark: the player sends short structure or signal pulses, watches nearby 3D geometry appear as a fading point cloud, then navigates from memory before the echoes disappear. The run is organized around three relay stations and a sealed destination called the Well. Sonar has a local charge and heat model, so repeated pulses are limited rather than being a permanent visibility toggle. Structure mode reveals architecture and surfaces; signal mode emphasizes relay and signal geometry. WASD controls movement, arrow keys control the camera, Space sends a pulse, 1 and 2 switch sonar modes, E interacts, and Shift increases movement speed. Echowell contains collision handling, local run persistence, relay progression, an ending state, locally synthesized sound cues, and bounded point-cloud rendering intended to remain responsive on modest hardware. All facility geometry and gameplay code are packaged with the extension. The game does not require an account, cloud save, remote assets, analytics, or internet access after installation.