I read on the store page it doesn't have menus, that can be fine, though minimalism shouldn't mean no basic functionality, but I was wondering if it has undo. 60 levels supposedly taking 5-10 hours seems a bit much, unless it's because you have to restart complex levels from the beginning after a mistake or something. also, are there any timing-based sections or parts that require quick reactions?...

No menus, no achievements, just you and a puzzle. I think a game like this would have a much bigger audience with Steam Achievements, if not one for each puzzle then at least one for completing the game.