Donkey Kong is a port of the 1981 arcade game of the same name, released as a launch title for the Nintendo Famicom.

It's the first ever ROM hack made by S.D.A. that is not a translation, although it is very simple. Here, the Jumpman sprite is changed to the Mario sprite from SMB1.

This was made from the simple fact that if you notice, the Jumpman and SMB1 sprites (at least the walking sprite) are really similar. Here are the only changes:

Original Jumpman sprite replaced with the SMB one (except for the climbing and death-lying sprites which were intentionally left as they are, while for when the player picks up an hammer the graphics are simply modified).
Hammer powerup is now changed to the SMB1 style.

Two patches are available, one for the 1983 ROM and the other for the "Original Edition" ROM (the one with the additional "Pie Factory" level).

August 5 update: Even if this hack was a success, S.D.A. hated it and so he took it down.

1983 ROM:
No-Intro Name: Donkey Kong (World) (Rev A)
(No-Intro version 20130731-235630)
File SHA-1: D8DFACBFEC34CDC871D73C901811551FE1706923
ROM SHA-1: D222DBBA5BD3716BBF62CA91167C6A9D15C60065
"Original Edition" ROM:
ROM not found in Database: No-Intro
File SHA-1: EE3603417CCB2058866B6C16396503609EF272AE
ROM SHA-1: A017A0A0AEE71FEA7BCFCB5D889E710516AB330C