I play a lot of games, but I don't review a lot. This one deserves it. It's one of my favorite games of the last 10 years, maybe of all time. The writing is excellent, I lost track of the number of times I laughed out loud. The gameplay is great, there are lots of different styles you can play, and I was still finding lots of content I had never seen before on my third playthrough (Contact Mike cracked me up). The art and music fit very nicely. The world they've created here is bleak and depressing and foreign, but ultimately the themes should be recognizable to any human. I'd love to revisit in a sequel.
It's really terrific in what it does. The visuals are very nice, the puzzling is clean and generally intuitive, and the puzzles build on each other nicely. Generally it isn't overly difficult, but you may run into a few moments of getting stuck. Once you figure out what was blocking you, you'll probably blame yourself, not the puzzle designer. It's worth buying at full price, but if it's on sale do yourself a favor and pick it up.
I wanted to like it, and in some ways I do. The graphics are beautiful, the puzzles are challenging, the story is intriguing. But I've never seen a puzzle game that punishes you so harshly for trying out solutions to puzzles. It's good that the puzzles are non-obvious (and in some cases, unintuitive). But if that's the case, the designers shouldn't structure the environment such that the player needs to spend an eternity walking, setting up the next possible solution, teleporting, walking some more, only to find out if the proposed solution will work or not. Maybe you'll have more patience for that than I did. Ultimately, I chose to uninstall and move on.