Once you get that patched ISO, you can play the complete game on PPSSPP with all DLC Shinkis, weapons, and missions unlocked from the start.

To properly experience the story with DLC characters, specific technical steps are required: Version 1.01 Patch

If you are looking to play this today, the "patched" version is the definitive way to experience the title.

You can tell if the patch is correctly installed if a star symbol appears in the bottom left-hand corner of the title screen. This patch notably adds the Kamikiri Maru shortsword to the Shinki Shop. Managing DLC

Busou Shinki: Battle Masters Mk. 2 (Japanese: 武装神姫 BATTLE MASTERS Mk.2

Ultimately, Battle Masters Mk. II is a meditation on obsolescence. The servers are gone; the physical toys sit dusty on shelves or sealed in expensive boxes, their voices silenced. Yet, in the digital realm of the patched ISO, the Shinki live on. They float in the void of your screen, their glossy eyes reflecting the digital light, forever loyal, forever fighting. They are waiting for a command that matters.

: While Mk. 2 allows you to import save data from the first game, it notably does not carry over your purchased DLC weapons or Shinki; these generally must be re-acquired or re-downloaded for the sequel. Installation & Setup Guide