Simply put, the PSP lacked the graphical memory (VRAM) to load the massive character models and environment shaders required for Storm 2 .
The PSP game that covers a similar timeline and roster is . However, because "Storm 2" is famous specifically for its cinematic story mode (which PSP hardware couldn't handle), I will provide the deep story breakdown of Ultimate Ninja Storm 2 , which is widely considered one of the best adaptations of the anime's narrative in gaming history. --- Naruto Shippuden Ultimate Ninja Storm 2 Psp Iso
Instead, play Ultimate Ninja Impact or emulate the PS3 version of Storm 2 via (on PC) or AetherSX2 (for PS2 era games). Simply put, the PSP lacked the graphical memory