The premise: we've been slacking off on this math course that we absolutely need to pass, and now it's the very night before the big final exam and, in the words of Sergeant Schultz, we know nothing, nothing!
So we take a (sleeping) powder and go to bed, to absorb our textbook's lessons by osmosis. The rest of the game, and it's a substantial game, is the navigation of a dreamscape, exploring mathematical concepts ranging from the simple to the complex. It's a puzzlefest, and it's all very educational.
Devised as they are around mathematics, the puzzles can get pretty clever. I particularly liked the roller-coaster puzzle. I won't say that the puzzles are all about doing math, though; I'd say, rather, that the puzzles are informed and inspired by mathematical ideas, or by anecdotes relating to the various mathematicians we meet. (Though we don't get to bean Newton with an apple ... unless that's an Easter egg I missed somehow.) I found it quite engaging. There's a lot of it, though: more than anyone could fit into a two-hour session, I'd say.
There's no real story to speak of, since it's all a dream and therefore allowed to be as disjointed as it likes. The whole thing exists to let us play with the puzzles. But I did think that, where the text wasn't there simply to teach mathematics, it was actually pretty decently written.
I guess it's really a very old-school sort of game, at heart. So I'm going with this being like the most breakfasty of breakfasts, the full English. A really, really full English, that should keep you fed all the way until tea time, with plenty of toast and a spot of builder's tea. Not the most elegant or eye-catching, perhaps, but just enough flavour and quite satisfying.