The game all about colors, shapes, and numbers. Your character is a red/green/blue circle/triangle/square; your enemies are walls that have holes with similar attributes.
Help your character reach the finish line by fitting through those holes. Be prepared to face new difficulties on each level. Don't be afraid to use different items from the shop if you're having some troubles. Be patient, and you'll overcome every obstacle this game has to offer, and very soon, you will beat it.
Good luck, have fun!