@Vyk: The game has 4 endings, if my memory serves well. Two beating Richter before and after getting the holy glasses, and two beating the inverted castle before and after 200%.

@Forbidden: Then or your game is corrupted or with a glitch, or your psp is loading a lot of things at the same time. Maybe you have used it for too many hours without rest. Even when connected to the main, it doesn't mean that the psp will not forced. Like any other instrument with memory RAM, the memory fills after some time or the processor starts to be forced to do a lot of tasks. If it is this, you need to reset it (turn it off completely, let it some minutes, an hour if possible, and turn it on). Make a coffee break during that reset, if that doesn't work, you'll be relaxed enough to search for another solution.

Has this happened to you with another game?