A portion of a Siliconera interview with Beenox Studio Head, Dee Brown...
S: What is the Nintendo 3DS version of The Amazing Spider-Man like? Retailer descriptions say that only the HD versions are open-world. Will the 3DS version be close to the console versions at all?
DB: The Amazing Spider-Man for the Wii and for the 3DS is actually based of the same code base and game assets which means that they share the same gameplay.
All players will get to experience the story, and of course, Spidey’s iconic web-swinging. We’ve optimized the experience on the Wii and 3DS to take advantage of their unique platform differences and motion controls, which means that players will have a different experience with the game on those platforms.
While the Wii and 3DS versions won’t have Spidey “roaming” between story missions, there are still plenty of collectibles, unlockables, and in-game challenges awaiting the wall-crawler, on top of large areas to sling through and intense combat with numerous enemy types. The Wii takes combat and web-slinging to new levels of immersion thanks to its motion controls, and the 3DS version will also have several unique mini-games that use its touch-screen. The NDS version follows the same storyline, but is an entirely different game with platforming elements.
If held side-by-side, all of the “level based” missions are very similar to what will ship on the Xbox 360 and PS3 platforms, just optimized to fit the Nintendo platforms’ unique capabilities.
So it appears that 3DS, DS and Wii are getting the really bad treatment as even the mobile game will support free-roaming and a really nice combat system that was first see in Ultimate Spider-Man: Total Mayhem for iOS and Android.
Although there is no trailer for the above versions, check out the mobile's trailer and decide whether you should pick it up for your iPad over your 3DS (and it will probably be reasonably cheaper.)