This is a nearly complete prototype for Donkey Kong Junior made on the last day of 1983. This prototype only has a few minor differences:
Some values in the lookup tables are changed so Junior is able to climb the ropes on the chain scene a few pixels higher in the released version.
The prototype contains additional 10 bytes of code at $85d3 that appears to affect size of Junior's hitbox in some way. One of the noticable affects of this is that the birds on the spring board screen will pass through Junior's bottom when he is at the very top of a vine which does not happen in the released version.