If you looked at recent Xbox 360 and PS3 game Catherine from developers Atlus and thought the puzzle mechanics looked interesting, but the premise was a bit too odd for your tastes, then I've got the perfect game for you! Robo5 from Yuguosoft is a delightful and charming game utilizing the same aforementioned puzzle mechanics, not to mention fantastic art and music, and a fairly intriguing story.
The story is told throughout the game play segments, so it can be easy to miss details, but I'll do the best recap I can. Basically, Robo5, our protagonist, wakes up in a strange facility wondering who he is. As a robot with free will and something of an identity crisis, he rebels against the mean and abrasive artificial intelligence program LA and tries to escape the facility, seeking the kind hearted AI, LY . LA talks to you throughout the entire game, giving you story bits and taunting you, like a less genocidal version of GLaDOS of Portal fame.
The puzzles all consist of manipulating boxes to reach an escape vent. Boxes follow the same rules of Catherine, where they defy gravity and stay in place as long as they're connected by an edge. In this game, you don't have an annoying voice saying "Edge" every single time you make a move, though. This mechanic makes for some real mind bending fun as you try your hardest to unlearn what you know about physics. Add to that several special blocks, such as exploding, electrocuting, floating, and crumbling ones, and It only gets worse. Should you royally mess things up, there is an "undo" button, allowing you to go back pretty far. I believe Robo is leaking energy, or something, and finding the collectible items on each map is supposed to replenish him. Apparently there were some translation errors, so it might not just be that I didn't pay enough attention to the dialogue.
At the end of each level you are rated out of three stars for completion time, energy cubes picked up, and how much energy you expended, I think? These stars eventually unlock challenging bonus levels accessed from the Diary. This game has five worlds with 40 levels, eight bonus levels, and even two different endings. The main problems with the game are the occasionally unresponsive and finicky controls. You can get used to them eventually, but they'll probably get on your nerves. If you've already played Catherine, you might get especially mad at the controls, as they are obviously much more limited.
The graphics are great looking, mixing 2D and 3D with a steam punk mechanical aesthetic. The soundtrack is excellent, and the story can be surprisingly compelling. The control issues don't stop the game from being tons of fun, especially if you like challenging puzzles. Game Center achievements and leaderboards are supported and the game can be yours for just one dollar. If you really wanted to play Catherine, but had no interest in all the nightmarish role playing and dating-sim aspects, pick this one up immediately. It is about 1/60th of the price, after all.