Flags allow to skip gathering 3 stones and go straight to chaos cave + farm there repeatedly by killing those roots and teleporting to flag at 0 food cost to respawn them instantly. It takes under 30 mins since start to kill first root (and get massive power snowballing) thanks to that. It takes some practice to make enemies walk into range of charged attack (without getting hit yourself), but it's totally worth it in the end~That works too, I just enter/exit the gorilla boss room to respawn them.