As part of one of the many petty, savage feuds in Greek mythology, King Sisyphus was forced by Zeus to roll a boulder up a hill and watch it roll right back down as punishment for his murderous, greedy ways. But also, mostly, as punishment for thinking he was cleverer than Zeus. Designers Matt Thorson (TowerFall) and Noel Berry (Skytorn) are currently working on Celeste, a game that’s sort of abstractly Sisyphean: there’s no boulder except the boulder of difficulty you have to shoulder as you guide redheaded Celeste through its 90+ levels. Initially created as a quick, hard-as-nails platformer…