Summit is a 2D climbing game. Towers are generated from a fixed seed so the same map is the same for everyone, the physics are real (Rapier2D under PixiJS), and the rest is you slowly working out that you have made a terrible mistake near the top.
The live version talks to an Axum WebSocket server for other climbers and a leaderboard. The archived snapshot strips that out: no server, no bots, no leaderboard. Just you and the tower, offline, forever.