That's what I figured too. If they make it a real game, they'd have to include a memory card, maybe 256 MB, for real saves.
The fact is that truly good games for the PSP have been very scarce. (There are a few.) I think one big problem is that the analog nub stinks on ice, so it's difficult to deliver on the promise of 3D, first- or third-person goodness. Porting PS2 games produces mediocre results. Porting a heavyweight PC game like Oblivion can't be a good thing.