All the Mario games I've ever played have hidden levels. I've never played a Mario Kart game before and the race/levels content seems a bit short. So I'm curious if there's hidden levels/races to unlock, or if wysiwyg is the rule here?
In Mario Kart 7, there are 8 cups of 4 levels each, of which only 2 cups are unlocked from the start. This means that Mario Kart 7 has 24 unlockable levels. However, no level is hidden more than so, meaning "what you see is what you get" indeed.
All cups can be unlocked by winning the immediately preceding cup. However, this only unlocks cups for the same engine class or lower. For example, beating Flower Cup in 150cc unlocks Star Cup for 100cc and 50cc, but doing the same in 50cc only unlocks Star Cup in 50cc.
In addition to the cups, there are 6 battle levels. Also, some regular levels have hidden shortcuts and paths, making them bigger than they appear.