yeah, i think it's in a kind of middle ground where the core gameplay and things like the camera already look a lot more polished than some fully complete games, but some of the stretch goals seem like they maybe should have already been prototyped and playtested (co-op especially) before they made any promises. also the one area they've shown off is very playgroundy, which doesn't say much about how the actual level/mission design's going to be.
im not a big fan of stretch goals in general, because there's an obligation to deliver on them, even if it turns out the budget could be put to better use elsewhere, or the promised feature sounded better on paper or doesn't end up working out (im very skeptical about the n64 shader)