Unlike the main console version of the game, The Forgotten Sands on the PSP is a side-scroller, with a separate story to complement the other games.
From the publisher:
Embark on an adventure to an exotic land and unleash your legendary moves on enemies as the acclaimed Prince of Persia: Sands of Time story line makes its return. Unfolding with the mystery and powerful narrative that have become classic elements in this series, Prince of Persia: The Forgotten Sands challenges you to unleash powerful offensive attacks and destroy your enemies. Race against time in an unforgiving world as you experience the return of the vaunted Prince of Persia.
Journey to a land of legendary combat and mysterious circumstances in this new installment to the Prince of Persia: Sands of Time franchise. Prepare yourself for impossible battles and know that you will come face to face with death as you engage in deadly combat. Experience many of your favorite elements from the original series as well as new gameplay innovations. The mystery and magic of the old-as-time fight between good and evil comes to life with all its rewards and consequences in Prince of Persia: The Forgotten Sands.
* Latest installment in the Prince of Persia: Sands of Time story line
* Encounter enemies determined to take you down
* Confront the danger that lurks around you in a land of mystery and intrigue
* Unleash powerful offensive battle measures against opposing forces
* Face off against well-matched enemies in battles of deadly significance
Marking the next-gen console debut of Ubisoft’s critically acclaimed series, Prince of Persia - The Forgotten Sands is the next chapter in the fan-favorite Sands of Time universe. Visiting his brother’s kingdom following his adventure in Azad, the Prince finds the royal palace under siege from a mighty army bent on its destruction. His brother Malik decides to use the ancient power of the Sand in a desperate gamble to save the kingdom from total annihilation. To save the kingdom, the Prince must embark on an epic adventure in which he will learn to bear the mantle of true leadership, and that great power often comes with a great cost.