The purpose of the hack is to create a 3rd/4th Quest for the game. Q3 is similar in style to the original 1Q, but 4Q takes more liberties. There’s no new graphics or any of that stuff. It’s meant to feel like an extension of the original game, as if development continued on and two more quests were created.

Slightly modified overworlds for both quests
8 new dungeons in new locations
Items shuffled around between dungeons
Shops changed
Important locations altered
Off-map rooms in dungeons (and overlapping screens)
2nd Quest: lots of hunting for heart containers!