pro
Ibb and Obb deserves a healthy dose of praise for the original game mechanics alone. As a cooperative 2D puzzle-platformer, Ibb and Obb treads new ground with its unique gravitational gameplay dividing the screen into two opposing worlds; one with normal gravity and one with reversed gravity, with portals connecting the two. Exploring the world and its properties is a joy and you need to work closely with your partner in order to progress, discover secret levels and find collectibles in the form of diamonds. The controls feel tight and the jump is perfectly tuned somewhere smack in the middle of floaty and twitchy.
pro
A great Portal-esque co-op feature is how you communicate between Ibb and Obb, by drawing a continuous line with the right thumb stick. This allows you to show your ideas to your partner in real-time while discussing it through voice chat and then execute the plan.
pro
The soundtrack is just perfect for the game. The warm melodic electronica is made by Dutch artist Kettel (Reimer Eising) and it reinforces the playfulness and atmosphere in the game. The sound effects by Tomasz Kaye also work great in tandem with the music.
pro
When faced with a particularly difficult timing based obstacle you soon realize that you can overcome it by solving a brain-melting puzzle instead, which is a pleasant surprise and makes progressing the levels much more rewarding. The emphasis lies in solving the physics based puzzles, and while you will die repeatedly testing your theories, the checkpoints will let you retry the puzzle almost instantly.
pro
The minimalistic graphics are adorable and so are Ibb and Obb and pretty much all the inhabitants of this delightful world. The color theme is somewhat muted and reminiscent of Thomas Was Alone in its style. The overall design of the game, from menus to characters, are charming if you're into that kind of thing.
pro
A fantastic little silly dweller are the "Fins" scattered around the world. They look like small tennis balls which you can easily kick up into the air and start juggling. There's even a Trophy for successfully bouncing a Fin back and forth between Ibb and Obb ten times. The Fins can also be used to snuff out enemies.
pro
You can play the entire campaign online or offline with a friend or find a partner in the online lobby.
con
The single player version of the game allows you to control both Ibb and Obb at the same time, using both sticks. This mode seems most likely suited for ambidextrous videogame savants and doesn't add anything of value to the experience, except frustration.