Elebits
The second-to-last mission is a salute to the physics engine, a massive sandbox in the theme park, where in the end you'll be throwing entire rides around. It's exemplary of the slowdown issue, but also of the fun you can have tossing stuff around.
The last mission is an obligatory boss fight, which mostly serves as a showcase for the single worst part of controlling the game, parts which require you to twist the remote with your wrist. Luckily it's pretty short.
The story in general is fairly brief, but, I think, just the right duration for it to keep from being stale. On the whole I would rank Elebits as the best one should rationally expect from a near-launch title (Twilight Princess being anything but the norm).
The level editor is, at least as far as I'm concerned, just hard enough to control/use that making new levels to fool around with is more trouble than it's worth. But going back to existing story mode levels for fun is easy enough.
Progress: Finished Story Mode: King of Curiosity