During the development of a game, lots of concept art will be made that demonstrates how the company making it wants it to look and feel when it's finished.

Usually this art is hidden away, never to be seen by people outside that company, but Rovio has just sent us some awesome behind-the-scenes images to show you.

Take a look below at how the game's environments and tracks started out in life.

Air track 1 mid-section
Air track 1 start
Air track finish line
'Bird' Mountain
Rocky Road Cave Entrance
Rocky Road cave start
Seedway landscape
Stunt waterfall track section

How well do you think the developer stuck to its original concepts? Spotted any big differences between these bits of art and the finished game?