Tiny Brains is a co-op puzzle adventure created by Spearhead Games, a team of wacky designers with some former Assassin's Creed, Army of Two and Dead Space members on board. The studio's goal with its first release was to make a truly cooperative experience that, in their words, is "super fun". Mission accomplished, Spearhead! Tiny Brains is some of the most blindly entertaining co-op action you can find, with just the right mix of puzzles, action sequences, and miniature chickens that go squish.
The basic idea behind Tiny Brains is that you control tiny lab creatures that have developed superpowers (semi-super, at least) after being experimented on by a mad scientist. Now they're trying to escape from the lab that holds them, busting through test chamber after test chamber in pursuit of freedom. Delicious, cheese-flavored freedom.
It starts with a few simple rooms to test your salt in a variety of situations. Push the ball into the goal, get the battery to the connectors so you can raise the cage, don't let the sawblades meet your squishy body, that sort of thing. A pink chick suddenly appears in the laboratory (as in, the baby chicken variety) and starts doing things like pressing buttons and breaking walls. When Pinky encourages the tiny brains to hop out the window, things suddenly get a lot more dramatic.
Each of the characters in Tiny Brains has its own ability along with a distinct color. Dax the purple ultrasonic bat has a handy skill that shoves things away, pushing blocks across the screen and over gaps. Stew, the highly-charged green bunny, is the inverse of Dax and can pull objects towards him. The red mouse Pad can swap places with just about any movable object, useful for placing yourself in out-of-reach areas and getting blocks down from odd locations. Minsc the cold-fusion hamster can form a rectangular block of ice that will stick around for a few seconds. This can hold down switches, block things from rolling down undesirable pathways, give characters a height boost, or even function as a surfboard!
All of these abilities are useful on their own, but since Tiny Brains is a game of cooperation, they have to work together to actually be effective. Each power has its own subtleties you'll learn to utilize and exploit. When trying to get a block to a specific location, for example, it's generally easiest to get Pad to swap places with it. His power can target at long-range, but unless he has a clear view, teleportation is a no-go. Instead, grab Stew and break out the attraction power. Its range is limited, but it can move objects located at steeper angles. Also, try loading everybody on top of an ice block, then using Dax to give the thing a shove. Fun times!