METAL SLUG XX for PSP system is the new addition to the famed METAL SLUG series that captures all the glory of the arcade experience and more. After General Morden is defeated and captured, a mysterious army arrives from the future to save him. They reveal themselves to be Mordens army from the future, and their goal is to provide their future leader with special advanced weaponry to take on his enemies in the present. Classic METAL SLUG characters Marco, Tarma, Fio, Eri, Ralf, and Clark return once again to take on General Morden and his new and improved Rebel Army.