Here are the list of changes that was made to the remake of FF IV. Some that we know about, some that we didn't know

Final Fantasy IV DS: SNES To DS Changes


You now control Cecil in battle in the opening sequence

New flashback scene of Cecil/Kain dueling in Baron Castle

Additional dialogue between Cecil/Rosa in Baron Castle bedroom (?)

Extended scene in village of Mist between Cecil/Kain/Rydia

Rydia has a new companion, the Pochika

Subtle map changes to towns and dungeons (ie: On the peak of Mt.Ordeals, instead of a small shrine, there is now a stone tablet which teleports you to a shrine)

Namingway has a new job as Mappingway (changing names appears to be unavailable due to voice acting)

Decant Ability System

Auto Battle System

Auto-map, rewards for 100% exploration per level

Cecil cannot equip bows or staves

Cecil gains more white magic spells (protect, shell, raise)

New magic spells Ultima, Faith, Brave, Bubble

Arrows are not consumed when shooting a bow, and come in quantity of 1 from chests

Characters rejoin at set levels

Tellah is now able to earn sufficient MP above 90, with sufficient level ups. (thus allowing meteor to be cast early.)

Bosses are generally harder and have new attack patterns

New Hidden bosses

Kain and Palom are now right handed

Item capacity increase

Switching weapons mid-battle takes up a turn

Gilbert can select songs to perform

Bows are fixed on the right hand, while arrows are fixed on the left

Bows no longer cause extra damage to flying targets

Spears no longer cause extra damage to flying targets

Child Rydia learns different spells over the long run

Various characters have different stat gains

Stat changes past level 71 are no longer random but controled by equipped decants

Spell damage has increased for most spells

Bio damage reduced

Can use spells from the magic menu without going back to the main menu after each turn

Every character except Cid naturally gains MP

Edge can no longer equip claws

Exit/Warp is disabled in all Castles and towns. (prevents bugs, like fetching the dark crystal early.)

Warp is completely disabled in the Sealed cave. you now have to walk all the way back out.

Warp now puts you at the start point of the previous room.
Elixirs can now be bought (from hummingways).

Bahamut's megaflare attack cannot be reflected.