I really liked 2001: A Cube Odyssey. Okay, it's called Fez, but like Kubrick's epic, I'm going to recommend this game and tell you that it's challenging and artistic and generally great. I'm also going to tell you what a piece of ♥♥♥♥ it can be and why some might be turned off by it (again, like 2001).
Fez carries a similar theme of striving to engage with things beyond our understanding. It also mirrors neatly the invetervention of a vast alien intelligence in the affairs of a primitive people, And, before you ask: yes, things get trippy and a bit pretentious toward the end and, yes, no matter how firm our grasp on the physics of things Fez will always have inexplicable bits beyond the ken of our primitive monkey brains.
Our vast alien intelligence du jour is a cube. Yup, that's right, a cube: one of the platonic solids, a d6, one of the basic units of Lego, those dang boxes you'll be pushing in almost every video game ever. But, hey, you're a cool 2D dude living in a 2D world so it totally blows your mind, man. Also, it gives you the ability to rotate the world around its axis, showing you hidden sides of things and allowing you to rerrange the environment along your 2D perspective to solve puzzles. And, if I haven't tortured the 2001/Fez comparison enough, quite a few of those puzzles will make you feel like a baboon impotently smashing a bone against a futuristic space monolith.
Fez delivers all of this through retro-style pixel graphics hung over a 3D frame. Everything is colorful and appealing and each environment is vast, but carries its own distinct tone and character that keeps exploration exciting. It's just a visually charming game. Well, there were one or two bits with harsh flashing and garbage that made my eyeballs want to jump out and commit seppuku for the harm they were doing to my head, but mostly visually charming. Yeah, sticking with that.
Your goal in Fez iso to collect cubes and cube fragments through platforming and solving puzzles. While platforming you rearrange the world to create a path for you to climb and jump up to get collectibles and reach new areas. Falling to your doom just places you back at the ledge you fell from and there are few other hazards. It's casual in the sense that there is no combat, but there are a few sections where the timing and precision required are viscious. Most of these are only for 100% completion; not necessary for the basic ending.
The platforming challenges will test your logic, but won't tax you to your limits. As for the "puzzle" puzzles, well, that is your hardcore experience, mister gamer man. Some of the puzzles will require you to observe and relate hints from locations spanning the game's massive map. Areas you might not have been to in hours. It will test your cryptography skills and even your ability to think outside the game. Some of these are quite clever, but many of them will be those sorts of puzzles where you either get them quickly or you never will. I think where the game missteps badly are its small number of puzzles that ask you to use resources beyond the scope of the game. While almost anybody playing Fez will have internet access and the power to decipher a QR code, for instance, some people will likely stumble on what they require to do so, and, more isidiously, puzzles like that tell the player that not all the puzzles in the game are self contained. Since you've been quite clearly told you need outside knowledge for a minority of the puzzles, you might go looking outside the game for answers when a little more patience and exploration could do the job.
Now, my stupid self will shout those puzzles down as being "unfair" and then take them behind the shed, while you might be some enlightened space being who finds ciphers based on that bit about the fox and the dog and the English language quite dull. Either way, none of the worst puzzles are needed just to get the normal end.
There are also three puzzles based on obscure moon logic that I'm pretty sure only specialists and/or the combined force of the internet were meant to solve. Solving these does basically nothing and doesn't detract from the game, though they are included side-by-side with the games other puzzles with no ceremony whatsoever. What I'm saying here is: to enjoy Fez, you've got to pick your puzzles, be okay with walking away, and try to be patient for a little while before you spoil them for yourself. That's how you'll get the most fun out of the game.
And it is a fun game! A really fun game, even! So pick it up and get ready to rotate your brain!
P.S. If you're on the fence about getting Fez because you've heard that Phil Fish is a righteous ♥♥♥♥, my advice is just to get it. From what I've read, Phil seems like a guy who just doesn't handle people well and could maybe use some anger management, rather than somebody with genuinely bad intentions. Ultimately, I don't know the guy well enough to make that judgement and I don't think the media has given a broad enough perspective on him for anybody who doesn't know him personally to make that judgement. What I do know is that Fez is the result of several people's hard work and is a cheerful, inclusive, brilliant experience. It's worth a few bucks on its merit alone and anybody who created it can't be all bad.