November 02, 2012
The titular character's home world is an 8-bit arcade game called "Fix-It Felix, Jr." which is partially based on Donkey Kong. Most notably the game starts with an introductive cinematic of the main villain, Wreck-It Ralph, climbing a building and then wrecking it, similarly to how Donkey Kong climbs the buildin under construction and then stmps shattering the ladders and bending the griders. The gameplay of the game is very different though, since in it the titular character has to fix the building rather than rescuing a character.
The border of the screen is also similar to Donkey Kong's, showing artworks of the characters.
The title of the game is very likely a reference to Donkey Kong, Jr., but while that was a sequel to Donkey Kong, it can be assumed that this game was called "Jr." only because of Felix inheriting the magic hammer from his father in its backstory. However it is never directly stated that this is the first game in the series and that there wasn't a previous game starring Fix-It Felix, Sr.
Because of these similarities of the game with Donkey Kong, Fix-It Felix, Jr. and Wreck-It Ralph are undirectly based on, respectively, Mario and Donkey Kong. Ralph's similarity with Donkey Kong is almost exclusively in his role, being the villain of the game, but moved by anger because of him suffering an injustice, in Ralph's case being the stumped where he lived being moved to the dump in order to build the Niceland building, while for Donkey Kong it was him being caged and mistreated by Mario. Also, the way he tries to redeem himself and being a "good guy", is similar to Donkey Kong actually becoming the hero of his own series starting with Donkey Kong Country.
Felix, on the other hand, is more directly based on Mario, being a carpenter and wearing similar clothes, most notably a cap with his initials on it ("FF"). In early concept art for Felix, his 8-bit sprite was desinged even more similar to Mario, sometimes wearing overalls, and sometimes having the same color scheme. Being armed with an hammer is likely a reference to Mario's weapon in Donkey Kong, also considering that in an early version of Fix-It Felix, Jr. during development, there were various hammers around the level, like in Donkey Kong. Additionally, Felix's jumping position is the same as Mario's, with his fist up, and also his dying animation, shown when Ralph accidentally makes the ceiling fall on him, is the same as Mario's in Donkey Kong: he spins around and then falls on his back with his legs up. The only difference is that while a halo appeared over Mario's head, Felix holds a flower in his hands instead.
An additional little reference to Donkey Kong is in an original character seen in crowd scenes, most notably at Felix's party, which is a monkey wearing a red tie, therefore looking like a cross between Donkey Kong and Diddy Kong. The tie also has a star on it, which is Diddy Kong's symbol.
Disney was licensed by Nintendo to use elements from their series in the movie, but they only included subtle references to Donkey Kong.