Looking at the PSP specs in Wikipedia, it seems too weak for running Hatari at acceptable speeds. I've tried Hatari on similar speed ARM.
One would need to use really old Hatari version (less accurate emulation is faster), disable music from game (if possible) to lessen interrupt emulation load, disable sound from Hatari to save CPU (and because breaking sounds is pretty horrible), use frame skipping and disable zooming. And if game works without it, disable "more compatible CPU" option. Maybe also disable spec512 (extra colors) support.