Peter Parker as Mickey
Ben Reilly as the Prince
Eddie Brock as Goofy
Mary Jane Watson as Pluto
Gwen Stacy and Harry Osborn as Donald
Norman Osborn as Captain Pete
Jason Phillips as Lieutenant
Curt Conners as Professor
Instead of chasing after a dog, Peter simply asks to be let in.
Also, Peter and Ben are both given love interests in the form of Mary Jane and Gwen, respectively, with Mary Jane replacing Pluto, and Donald's role split between Gwen and Harry.
Gwen and Harry figure out that Peter isn't Ben, so they help him out.