Both Captain America and The Human Torch are voiced by Daran Norris. Both roles were also later played by actor Chris Evans.
In homage to the classic Marvel series "What If?", this game has a "What If?" mode that can be accessed by the password screen, introduced by the Watcher (as the original comics were). With this mode on, you can play through the game and observe the (frequently hilarious) changes that have taken place. Changes range from insignificant alterations to complete deviations from the original premise. It is not present in the Nintendo 64 version.
When wearing the Spider-Man Unlimited costume (the one that gives the power of invisibility), Spider-Man can turn invisible during the bank levels and walk up to the robbers, listening to them exchanging small pieces of dialog with each other.
If the demo screen if left running long enough, Spider-Man will be seen through a gun barrel like the beginning of the James Bond films and fire impact webbing toward the screen.
During "What If?" mode other Marvel characters can be seen in the background, including the Watcher (introduces "What If?" mode), the Silver Surfer (when Spider-Man is pursued by police and take a ride on the blimp), the Ghost Rider (very briefly seen driving down the side of a building at the very beginning of the "Race to the Bugle" level) and the Sub-Mariner (seen outside during the battle undersea with Carnage). The Sub-Mariner even gets an entry in the game's character database.