Nintendo 64 emulator fork adds rollback netcode to multiplayer classics

Classic Nintendo 64 multiplayer just got a modern second life. RMG-K’s v0.9.4 update, released May 14, folded “Rollback Gameplay Into Kaillera” into the fork’s multiplayer stack, which means any multiplayer N64 game running through it can play with far smoother online timing than the old delay-based approach allowed.

That matters because the N64 era was built for living rooms, not unstable internet matches. Delay-based netcode asks players to wait for remote inputs to arrive, and on a fast fighter or a tight party game that delay turns every button press into guesswork. Rollback works differently: it predicts inputs, corrects mistakes by rolling back frames when it has to, and keeps the game feeling much closer to local play even when latency is ugly. GGPO, the rollback networking SDK that helped popularize the technique, pioneered rollback networking in peer-to-peer games back in 2009.

Kotaku reported on May 17 that the impact goes far beyond Super Smash Bros. 64. The feature applied to any multiplayer Nintendo 64 game running through RMG-K, which is the kind of upgrade preservation-minded players have wanted for years. For speedrunners, fighting game players, and retro communities trying to keep match nights alive, the difference is not cosmetic. It changes whether old multiplayer design survives as a museum piece or keeps working as a living format.

The rollout also reflects how collaborative emulator work has become. The v0.9.4 release credited NyxTheShield, Jay-Day, and nickthename, and Kotaku said the rollback work was developed alongside original RMG fork author Jay-Day. NyxTheShield stood out as the main contributor, and their public YouTube profile identifies them as a Chilean composer and producer with work tied to Undertale and Deltarune-related projects. This is not Nintendo blessing the library with online play. It is the community doing what preservation scenes have always done best: filling in the gaps hardware never covered.

There is still a catch. A Yahoo Tech summary said the implementation was, at least for now, limited to two-player sessions. Even so, the GitHub release page showed v0.9.5 arriving quickly after v0.9.4, with host-list and join-behavior fixes signaling that the project was moving fast. For N64 multiplayer, the big shift is already clear: classics once chained to the couch now have rollback, and that gives them a real chance to stay competitive in 2026.