Unstabled Horse It's possible to jump over a platform horizontally to reach 2 spaces away, you can also do the same diagonally. With good timing you can do a circuit of 4 or even 3 platforms. These facts, plus the fact that there is a set solution and positioning for each wave makes it so I don't think there is a real upper limit for how high you could score.
Anyway, really fun game, I've probably spent four hours on it and they've all been enjoyable.