What you see above is iMovie running on my iPhone 3GS. And it's supposed to work on the 3G too. I guess it will work even better on the iPad. Here's a sample project:
However, there's some problems that do justify the iPhone4 official exclusivity:
Browsing existing videos is fast, but when it comes to a big photo gallery, it does slow a bit.
Export only works in the lowest 320p setting, and for simple projects (have to run more tests to see if it is the duration that causes problems)
That said, a Apple could easily have released a specific 3GS version.
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