Robot Bros is a relatively new Windows Phone game that plays like a platformer but has a puzzle plot. You take control of the Robot Brothers and have to navigate from start to finish while negotiating around a series of obstacles.
The challenge comes into play in that you can only control one robot at a time and both robots have to cross the finish line. Robot Bros has 90 levels with six robot types. In just tinkering with the game for a short time, it comes across as a challenging game. Robot Bros has recieved some nice reviews over on iOS and has the potential to do the same here on the Windows Phone platform.