I played the last five hours of this game in one long marathon session. That was probably a mistake. By the time it was done, my brain was complete mush. It's not so much that I was driven mad by the demon-haunted reaches of infinite space . . . but it didn't help.
The thing I admire most about this game is that it does something video games have always had the potential to do, but rarely attempt - it created a world that operates on fundamentally different rules than the real one. Okay, so all games do this to an extent, what with eating a mushroom to make you big or wandering into people's houses and clearing out their huge, conspicuous treasure chests with no legal or social consequences, but a simplified or fantastic world isn't really in the same league of unreality as a world where all parallel lines diverge and triangles have fewer than 180 degrees. Hyperrogue is more like a Rubik's Tesseract, something that can only exist in a digital form (the 4D Rubik's cube is a real thing, but the way). I like that a lot. Taking something that is well-defined mathematically, but completely impossible for the human brain to imagine, and then making it into a toy.
The thing I like least about Hyperrogue is the rest of the game. I know that sounds pretty harsh, but I don't mean it as an indictment of Hyperrogue so much as a statement of my own preferences and biases. The main thrust of the game is exploration, which I like, but then it puts you back at the beginning whenever you make a mistake, which I hate. Then there's the geometry-based puzzle that is navigating around the map, which is something I tell myself I should like, but in practice wind up hating.
Ultimately, it is a well-put together turn-based strategy game with an inventively designed world and heavy random elements. I can't fault it for not being exactly what I want from a game, but I'm glad that I never have to play it again.