The Ultimate!Spider-Man Dimension is more akin to our world than the Amazing!Spider-Man Dimension
To me, the A!SD seems more like a retroistic dimension (the way the levels are with its grainy cel shading adds to this too) while the makers have said the U!SD is based more like modern day comics. It would also be why Kraven is based more on his older incarnation than the currently ressurected version in the mainstream Earth-616 of Marvel Comics.- Probably because the Ultimate Spider-Man comics have always reflected a more modern feel than Amazing? This isn't WMG so much as straight fact.
The Ultimate levels are in continuity with the Ultimate Video Game
Because Parker's got to still be alive somewhere, Dammit! By that same token, the Amazing levels are continuations of Spider-Man: The New Animated Series
By virtue of "Same voice actor" And by THAT token, the Amazing world in the DS version
is in-continuity with The Spectacular Spider-Man, and presumably, Spider-Man: Edge of Time. By that token, Amazing's levels, alternately, being continuations of Spider-Man: The Animated Series
Taking the sequel, Edge of Time, into account establishing Mary Jane into Amazing's life, Amazing knowing who Madam Web is, the multiversal nature of the story, & the more classic feel of the levels, doesn't it feel like Amazing's levels could be set either during, or even after, that Spidey's series? The only downside is that Chris voices Noir in this game & 2099 in Edge of Time, but seeing as the games establish Mary Jane being alive, as was the intent had that show continued, so much of Spidey's rogues gallery of that show (characterizations can be forgiven because the bulk of Edge of Time takes place in an alternate timeline), & what I've already mentioned, couldn't it be possible? The "Ultimate" stuff takes place before Ultimatum
- During the Deadpool level, you overhear a commercial for Doctor Strange, who died during Ultimatum.
Venom was somehow the ultimate mastermind.
A crack theory, but this would explain Venom's mysterious absence from the game. He tossed Mysterio a fake tablet that did virtually nothing in the grand scheme of things aside of just make weird as hell illusions throughout the multiverse, and Mysterio never actually became a Physical God. It was just Venom using him just to screw with Spidey.