Taking inspiration from such games as Qwop, in this 2D game you have to maintain a pillar of cats.

You start as a solitary cat wanting to get to the bird's nest in a neighbour's tree, but with the fence in the way it can't reach the trunk to climb it. As it yowls other cats are attracted to it and they all jump on top of each other to try and reach the target branch. The player has to keep this growing pillar of cats stable via each individual cat, holding down the appropriate number key (each cat is assigned a number in order of its joining the pillar) and using the left and right arrow keys to make it lean forward or back. This is made especially difficult each time a new cat climbs its way up the pillar and upsets the balance of the existing cats!

The player wins when the top cat makes it to the branch! There will be a number of levels, each with a higher target.

Image source: http://farm3.static.flickr.com/2249/2214149648_5a980d4c26_o.jpg