PSone Game download Wild Arms Freezing

I've downloaded Wild Arms from the PSN store and have been playing it extensively. Sometimes the game slows down in battles and occasionally it just outright freezes and the only way to restart is by removing the battery from the PSP. I'm using a PSP 2000. Is that something that is exclusive to the game? Do all the PSone downloads freeze? Or, could it be something wrong with my PSP or memory card?

The PSX original used to freeze in battle from time to time on the PSX & PS2. not sure if it did on the PSOne..

Its more than likely just a side effect of emulation though :(