The two football teams in the game are the Dawgs and the Geefs, both references to two of Goofy's pseudonyms over the years, Dippy Dawg (his early incarnation) and George Geef (his "everyman" name from his 1950s cartoons).
On Goofy's shelf, behind the pictures of Walt Disney and John Lasseter, there's a picture of Goofy in his first appearace in the 1932 short "Mickey's Revue". At that time his name was Dippy Dawg
The model number on the TV box is M1C-K3Y M0-U5E, Goofy wears a Mickey watch, and there is a picture of Walt Disney on his bookshelf. Also on the shelf is a picture of John Lasseter, autographed to Goofy.
This was the first Disney film to experiment with "paperless" animation. Half of the animation was drawn directly into the computer using Wacom Cintiq graphic tablets.
Among the players piling up on Goofy at the end are characters from previous Goofy shorts: Goofy and his horse from Dingo fait de l'équitation (1950), the stick figure golfer from Le golf (1944), and a hockey player from La castagne (1945).