I'm working on a multiplayer nostr game development library called disastr. 
It is based on Bevy, a game engine written in Rust.
Nostr relays are used to establish webrtc connections between the players. Rollback netcode (with ggrs: 
) is used by default. Games are deployed on the web (WebAssembly).
The idea is to make it easy to develop multiplayer nostr games without having to worry about identity management, networking, lag issues, and focus on writing the game instead.
There's a demo here with pongstr, a multiplayer pong game.
Codeberg.org
disastr
Nostr multiplayer game development toolkit
crates.io: Rust Package Registry
pongstr