Agent P: Rebel Spy
Web Browser Game
The game places the player as Agent P within the Phineas and Ferb - Star Wars crossover universe. The game features three levels, in each of which the player must fight their way past Darthenschmirtz's Normtroopers to rescue their fellow agents before battling Darthenschmirtz in an arena, where the agents they rescued return to help them out.
As you defeat Darthenschmirtz, he gets increasingly powerful, until you defeat him once and for all in the third level.