Well, they don't really resemble the fourth game... More like the third! Although, it certainly has its own unique style!
From the fourth game, they took:
1) The ability for the hero to attack
2) Some magical spells that weren't in the third game.
3) I don't remember anything else (I only played the fourth game twice)
From the third game, they took
Basically, everything else... And added a little of their own.
