drop a .bsp / .bsp.bz2 / .vpk map file you own
cleanroom-surf — CS:GO-style surf movement, clean-room engine. Drag & drop a .bsp you own (CS:GO surf maps, v20), a .bsp.bz2, or a Workshop .vpk — files are read locally in your browser, never uploaded.
Click the 3D view for mouse-look. WASD move, Space jump, R reset to stage start, F3/` debug overlay (collision hulls & triggers).