I didn't know the term rollback before, but it seems to be exactly the same thing as lag-compensation which is what's the standard in shooter games since Quake.

I didn't know the term rollback before, but it seems to be exactly the same thing as lag-compensation which is what's the standard in shooter games since Quake. These are usually not peer-to-peer, but use a central server instead; the server retroactively applies inputs from all players (within their latency window for obvious anti-cheating reasons) which are not dead, though some games don't have the latter restriction, which enables players to trade kills even with instantaneous hitscan. It results in the usual problems (peeker's advantage and being teleported backwards when a high-ping player kills you while you are moving) though it is not obvious how you can work around these.