Somehow, the HDR mod for Smash Ultimate (massive gameplay overhaul) has managed to shave off two entire frames of input delay.

1 frame of this is physics delay, which has been present in Smash since Brawl. As I understand it, this means that the game actually reads your input but due to the order the physics interactions are executed, it would result in a 1 frame delay on anything you do actually coming out.

The other frame is just general input lag. Apparently, they're squeezing the Switch for all its worth because you can't use sysdvr, a recording/streaming homebrew tool, anymore. I wonder if overclocking would help mitigate that.

Smash Ultimate with HDR is now down to 5 total frames of input delay (83.3ms). Insane progress.