I have DDK game and was wondering if i can add the new levels to it like you did?
Nope, you would need a different board. DDK runs on a Donkey Kong Jr. board and
Donkey Kong 2 will only work on a Donkey Kong board. That is why I went with individual boards (DK & DK Jr.) with a manual (printer) switch. I hope to add Donkey Kong 3 and Radar Scope sometime.