It was probably the first hack to use hex editing to change its text, and is currently on version 1.2.
Many tiles and sprites are the same as the original game, but recoloured.
The bricks and stones were likely textures taken from Google Images and modified.
The animated scenery, and gunner aliens, were taken from a sprite sheet somewhere.
The Thwomp was taken from the Mario & Luigi series.
The spaceship, the star, rainbow road, the bottom of the title screen, and Rover were sprited by Michael alone.
The arrows are from Yoshi's Island and the pirahna plants are modified munchers from Super Mario World.
The backgrounds are most likely stolen CBGs.