Originally released in 2010, Sonic Colors was the first of the Sonic games to experiment with the mixature of 2D and 3D gameplay that would come to further fruition in Sonic Generations. The Wii version is more remembered due to that, as the DS version used a 2D only dual screen gameplay approach. Prepare to use colorful wisp power to battle Robotnik one more time!
Here's a description from Sega:
The diabolical Dr. Eggman has hatched another plan for world domination!
He has built an amazing interstellar amusement park, floating in space around Sonic’s home planet, bursting with incredible rides and attractions.
However, all is not as it seems as Dr. Eggman has abducted an alien race and is harnessing their colorful energy to fuel a sinister plot. Before Dr. Eggman completes his evil plans though, Sonic discovers his mysterious theme park in space.
When he arrives, Sonic finds he is also able to use these alien powers and is ready to help. Sonic will need all his speed and skill as he faces this test, but, empowered by the alien energy, it’s a test he’ll pass with flying colors.