I wrote this awhile ago elsewhere, but here's what the DS version has:
- Touchscreen menus
- Option in the options to switch Kana to English for the touchscreen menus
- Map, top touchscreen
- Zetta joins you (after beating him)
- Worse graphics
- Lacks voice acting in a large majority of areas
- Healthy array of options
- Lag after attacks, comparable to what FFT was for the PSP
- Non-original music, feels "watered down"
- Introduction is by Norio Wakamoto
- Strangely, 4 levels of brightness of its own
- Identical button configuration from the PS2 and PSP versions
- Displays the real time in the top screen
- Three levels of zoom, "up close", "far away" and "in the middle"
- Lacks widescreen
- Pleinair is playable