With the trailer now officially out, differences from the original KHFM have been revealed.

Summary:
+ 14/3/2013 release date
+ 6980 yen
+ Director: Tetsuya Nomura
+ Co. Director: Tai Yasue
+ Producer: Rie Nishi

Points that have been changed from the original version of KH Final Mix:
+ On top of being made HD, some character models and textures have been updated
+ The English voicing has been changed to Japanese voicing
+ Trophy support
+ Custom theme made available after clearing the game
+ Addition of abilities 'EXP Zero', in which you cannot earn EXP, and 'Combo Master', in which combos work even if an attack misses
+ Camera controls have been changed to the right stick, R3 button to swing the camera behind to the default position
+ 'Talk' and some special abilities etc. now executed with the △ button
+ 'Summons' is in the command menu separate from 'Magic'
+ Also, the inclusion of Aerith, Leon, various Disney Characters and their stages etc. has been revealed.

Staff comments (some excerpts):
Gen Kobayashi, Character Art Director
+ A great deal of the base material had to be remade high resolution to fit the HD remastering
+ The menu screens have been made prettier, the picture has been made wider, and controls are nicer
+ Even if you played the PS2 version you can enjoy it, it will feel fresh
+ They have worked on many trophies and custom themes
Tohru Yamazaki, Team Leader of the Character Section, Osaka
+ Even now people look at the first KH title and say it is beautiful
+ With an aim to make post-KHII quality the standard, some texture resolutions have been drastically increased
Sumio Nasu, Programmer
+ Without anyone who remembered the ten year old program, they finally worked out how to progress after much trial and error
+ Wants to make use of the knowledge gained from this project to bring the next remastered title to life
+ Controls for this title feel close to that of KHII, you can also skip cutscenes