In this remake, there are two new enemies that weren't in the original or director's cut. They are Lisa Trevor, and Crimson Heads zombies.
A full remake of the original Resident Evil (1996), the new version includes an altered mansion layout with brand new rooms and enemies and new plot elements that take into account developments in the later Biohazard games. Also, the entire script was retranslated, eliminating the notoriously poor English dialogue that was present in the original.
The devices in which you have to put the MO discs in (to release the door to the prison cell) are actually slightly modified GameCube consoles.
The boss battle with the giant mutated snake and the Tyrant are largely unchanged from the original. The boss battle with the giant shark has been changed from a typical battle to a puzzle.
The game originally didn't have door loading screens as the GameCube was powerful enough to not need them, but fans disliked this decision so Capcom put them back in.