I don't understand the any% run in this game. There isn't any ending or credits... This doesn't seem like it completes the game at all.

I would think that any% would need to unlock the ranch and get the foal, which as far as I can tell, is the ending of the game...

The last race isn't unlocked until the first 5 are completed, that's why we don't count it in the any% run. We put it in the 100% run since it's a locked map at the start, where all the others can be played in any order.