Donkey Kong and Mario, then called Jumpman, make their first appearance in Donkey Kong, which is the Commodore 64 adaptation of the game released in 1981 on an arcade machine.
Jumpman must rescue his girlfriend Pauline, captured by the gorilla, by climbing ladders to join her.
Beware, however, of the barrels that Donkey Kong throws at you.
To avoid them, Jumpman can, as the name suggests, jump over them, but also destroy them using hammers.