This is super cool and I'm really digging it! Out of curiosity, the difficulty checks seem really high for the races. I know you can boost the result of the roll with your speed die and you can get help dice from party members, but the checks required seem particularly high. Is there something I'm missing?
I'm thinking like, your average roll on 2d12 is 13, your 1d4 speed die average is 2.5, and then you'll use an attribute that you have a +3 on, and you tack on a help die for 1d6 or 3.5 average. That gives you a median roll of 22. The difficulties go up to 30.
Does this not matter much because the final roll really determines who wins?