I´ll start this by saying just this: This game is a fucking masterpiece, and it´s easily one of the best XBLA games ever. It´s a completely awesome mix of platforming and puzzles (hard hard puzzles, not the kind of "puzzles" most games nowadays have). If you like both genres, this should be an instant-buy, although let´s go into some detail first:
If you haven´t seen the graphics, check some screens, a trailer or just better: play the demo. They are gorgeus pixelated graphics, with care and detail in every room in the entire game. In fact, the entire game is done on 3D, and it has plenty of cool effects over it. It´s one of the best looking games with pixelated style.
Again, the music is kind of classic, with melodies that are based on 4-8 bits ones, but they are really nice and they rarely get annoying. And even when the music is annoying, it´s intentional, it´s part of the game. It blends perfectly with the graphic and gameplay style, and I would go as far as to say that you will want to hear some of the tunes after leaving the game. It´s that good.
Ans this is the brilliant part of the game. Controls are really simple: move left, right, jump, talk, use, turn world to the left, and turn world to the right. With just that, the game will throw at you levels and levels where you won´t know WTF must you do to get that collectible or get to that door. It´s so simple yet so complex, that is hard not to love it. You will get the basic controls down in a few minutes, but you will suffer nearly everytime you find a new room.
The basic gimmick of the game is that everything plays 2D, yet you can twist the world in 3D, so unreachable platforms get closer, and you can get through paths that you wouldn´t be able to in either 2D or 3D. It´s a hard to explain effect, but you will learn it right away in the beginning. In fact, you will rarely get stuck by this gimmick alone. You can´t die in this game, so that really helps too.
All the levels in the game form a huge labyrinth, with tons and tons of collectibles, alternative paths, etc. But don´t think this game is like a classic platformer, because it isn´t. You will have to EARN most of the collectibles. And no, that doesn´t mean you will need ability to get to that collectible: you will need to use your brain, and a lot. You will have to brainstorm at each puzzle and try and retry until you find the solution. In fact, the game shows you from the beginning a map to know exactly where are you everytime, and even more important: how many and what kind of collectibles have you left on any room you arrive to. So it´s not a matter of just finding the collectibles, it´s a matter of learning how to get them.
I extremelly NOT RECOMMEND using a walkthrough, as you will get stucked in many places from just the beginning, but it feels so right everytime you solve one room. Think of this like Braid or Limbo, they aren´t that fun if you just look at the solution everytime, and if you look just once, you could spoil yourself similar puzzles, and you will get stuck in a few minutes again on the next one, as you have to learn to solve the puzzles.
The game has 32 cubes, 32 anticubes, 4 artifacts, some treasure maps and keys for opening some doors. You can finish the game with just 32 cubes of any kind, so you will surely be able to get to the ending. Unlocking everything without using a guide it´s on an entire different level though. You can restart the game with the option New Game+, so you can keep getting everything after finishing the game. You´ll unlock a nice extra too, but I won´t spoil it...
Personally I´ve just finished the game with just 32 cubes, so I have nearly half of the game to replay. I´ve played for more than 5 straight hours, so the game has a really nice length too. I would go as far as to say that I will enjoy replaying it. So it has a nice value for its price.
So far they don´t seem to be that hard, as you just have to play the game. Getting everything on it seems to net 200/200, so even if the game can be really hard on many parts, if you are a completionist, you will get it sooner or later. No play with x lives achievement, no finish the game in x hours achievement... Just complete 100% of the game. There isn´t anything missable, so it´s just a fact of playing and solving everything until you unlock them all.
Seriously, if you like platforming and puzzle games, BUY this game. It will blow your mind. It´s that good. I surely hope this game sells well enough, as this is a perfect example on how an XBLA game should be. And at 800 points, it´s just plain awesome.
Feel free to ask anything on the comments if it isn´t commented on the review. I know I haven´t been too specific, but I don´t want to spoil anything of this superb game to anyone.