Of course, none of that will be news to anyone who's played The Two Thrones. What will be news is that the PSP edition features a handful of new levels, which the Prince delves into every time he closes one of the "sand portals" his enemies have left lying around the game. These tend to be short and more plagued with camera problems than other levels, but they still make for a cool diversion for those who've already played Two Thrones.
Less cool are Rival Swords' plentiful glitches, which seem to crop up whenever the game is played for longer than 15 minutes. They especially like to appear during fight scenes, as you might flip over a guard's shoulders and suddenly find yourself 20 feet away, or whiff your sword through the air when there's a guy standing right in front of you. Also, if the game suddenly seems quieter than it should be, it's probably glitching, as the voice-overs and music will frequently cut out for no apparent reason. It doesn't affect the action, of course, but the story's a lot less compelling when you can't hear the constant bickering between the Prince and his darker half.
Story aside, Rival Swords also features a throwaway chariot-racing mode, which would be a lot cooler if the chariot sequences weren't the most frustrating part of the game. More interestingly, the game packs in the Prince of Persia saga's first real multiplayer, and while it's limited to an ad-hoc race between two players, at least the approach is novel. At the beginning of each of the made-for-multiplayer levels, you'll pick from three branching paths. There's one that's hard and fast, one that's easy and slow and another one in between, and if you get tired of one path, you'll be able to switch off when they intersect. Depending on which direction you choose, you'll be able to spring traps on your opponent, tripping them up as you inch closer to the finish line.