Ready for adventure!
As a gameplay experience, Captain Toad is on the lukewarm side, rarely presenting a challenge of timing or reflexes. For the most part the goal is to take some time, survey the landscape, and methodically "solve" it; collecting coins and gems while exploring the way to the level goal. It's about as low-action as a Mario spinoff can get.
But in terms of clever stages and cool world design, Captain Toad delivers wholeheartedly. Super Mario 3D World's aesthetics and level layouts were top-notch, and this is basically more of the same of that. Toad has picked up some new skills, too, when compared to the 3D World minigame incarnation -- including many of Mario's tricks from that game, such as platforms that move when touched, and the Double Cherry.
The amount of content seems to be pretty solid, although the game is a bit misleading about this: each storybook-like episode has a relatively small number of stages, and I didn't even know there was more than one episode until finishing the first and unlocking the second. There are three, apparently. So 50-or-60-ish stages sounds like a pretty good amount to me.
One complaint I have so far is that there's no way to turn off the gyroscope camera controls. It makes the game more difficult to play on the TV screen, since I'm never paying attention to where my hands are when watching the TV. Luckily this is a lot less noticeable when playing just on the game pad screen.
Progress: Finished episode 1, collected 54 gems