Are Save States A Thing?

[Shtrudel]

A year ago someone joined our community and showcased humself beating stage 50 on Difficult as Tamplate without taking any damage. He said he used extensive puase-buffering, but that alone can't elimintae human error for around an hour.
When playing with him online, he never showed such skills and by the time I was ready to question his methods, he vanished.

Is it possible that he found a way to use save states (meaning that he saved during his playthrough and reloaded whenever he took damage)? If so, that means LFR files have no value anymore.