Multiplayer gaming usually involves getting a few head shots in Call of Duty or dropping banana peels in Mario Kart. But while competition can be fun, nothing really beats working together. Ibb & Obb, which just launched on the PlayStation 3, takes this concept to its extreme, essentially forcing you to find a buddy to play with. You can play by yourself, but it's nowhere near as fun.

The game stars the titular pair of Ibb and Obb, two cute little blobs with eyes and legs and not much else. They can jump, but not very high, so getting past most of the obstacles in the game requires teamwork (one can jump on the other's head for a boost, for example). But complicating matters is the game's structure, as the world of Ibb & Obb is split into two halves, each of which has a different take on gravity. So if you hop through a portal into the bottom half, you'll immediately flip and start walking upside down. Enemies can only be defeated in one half, and many of the puzzles force you and your partner to split up and take different routes in order to continue. You can also hop between worlds in order to build up momentum and jump even higher, in a move that will be familiar to fans of the Portal series.

Ibb & Obb was a graduation project that eventually Richard Boeser, one half of developer Sparpweed, decided to flesh out into something much bigger. "I remember looking at a puddle after some rain and thought it would be great if you could jump through and end up in the mirrored world on the other side," he says. "The double worlds seemed really suitable for a side view world, and it slowly transformed into the Ibb & Obb universe."

You can play with someone else either online or on the same couch, and your experience will vary quite a bit depending on your companion. Many of the puzzles require a bit of outside thinking, so an extra set of eyes to help solve those problems is ideal — in Ibb & Obb, two heads are certainly better than one. There is an option to play solo, but it's incredibly difficult, as you use two analog sticks to control both characters at the same time. When both of them need to be moving simultaneously to solve a puzzle, well, good luck. Playing Ibb & Obb solo requires a degree of hand-eye coordination I certainly don't possess.

"Trying to shape that interaction into a meaningful and fun experience is something I find important," says Boeser. "This doesn't have to be co-op, but it does feel like a mode of play that hasn't been explored enough. Few games really focus their design on this and people seem to almost expect a single-player mode in the game. But when you see how much fun two players have solving challenges together, it seems weird there aren't more true co-op games out there."