Here’s a review for Yu-Gi-Oh! Arc-V Tag Force Special (assuming you’re reviewing the update/patch itself, not the full game):
The Process: Players had to manually download update files (often distributed via the official Konami website or Japanese gaming portals) and transfer them to their PSP’s memory stick.
File Structure: These updates were not typical patches that rewrote the game code. Instead, they were additional save files or database files that the game was programmed to recognize upon boot-up.
The Result: When the game loaded, it would scan for these update files, merging the new data (cards, icons, and pack lists) with the core game data.