Fast paced retro FPS with double jumping and wall running. Side project by the creators of the commercial game Sprawl which has an overall rating of "Very Positive" on Steam. Made in the Quake 1 engine. All game game logic is FOSS under GPLv2, its original assets are free for non-commercial use (CC BY-NC-SA 4.0) but it also bundles LibreQuake (MIT) for some stuff.

Official trailer: https://www.youtube.com/watch?v=q0S8-dLWUb8