The proof that "runs in the browser" holds for a real 3D game too. The foundation is a free open-source game; the work shown here is everything around it. Complete touch controls with a movement stick, automatic sprinting and aim assist make it playable on a phone, and the resolution adapts to weaker devices instead of stuttering. German is the default, English is a switch away. On top comes a server of its own: co-op matches by code with a lobby, room list and up to three AI teammates, accounts with passkeys, a leaderboard, profile and achievements. 17 automated browser checks guard the flows.