This video serves as a more in-depth review but I really recommend you to play it by yourself.
Playing PsiloSybil was an absolute blast. It was tough but never felt impossible or cheap. The controls were tight and the level design made use of the moveset seamlessly. I felt actual joy after overcoming what seemed to be the hardest level yet, only to be thrown into an even harder one.
It's pretty rare nowadays to find a game that actually challenges me the way PsiloSybil did. Y'know, without devolving into either Kaizo Mario territory or just artificially increasing difficulty by giving everything bigger numbers. It was really refreshing to play through a hard but balanced game. And knowing that more's to come, it makes me really excited for this game's future.