Seeing what appears to be an evolution inefficiency when reviewing best creatures of generations, especially for climbing when all creatures are at 0% fitness (initialization) and when all creatures are at 100% fitness (yet with more untapped potential in the body that creatures which do tap into it seem to go unrewarded for tapping into it), I'd like to suggest an alternative fitness measurement to address this; ((self)-(worst))/((best)-(worst))=x% [within generation].
That is, for either climbing or running; the creature within the generation that moves the most to the right (or falls the least to the left) will always be marked as 100%, and the creature that moves the least to the right (or falls the most to the left) will always be marked as 0%. For creatures between, their fitness is the % of the best that they reach after subtracting the worst from both itself and the best; so if the best climber falls -2m to the left and the worst climber falls -8m to the left, a creature that gets -5m will have a fitness of ((-5)-(-8))/((-2)-(-8))=3/6=1/2=50%. The best gets ((-2)-(-8))/((-2)-(-8))=100%, while the worst gets ((-8)-(-8))/((-2)-(-8))=0%; thus mechanically serving as the clamps for their generation.
I believe this would help optimize evolution efficiency most notably in climbing initiation, where with the current method if all creatures get 0% it doesn't (seem to, as far as I can tell,) matter if one fell -5m left and another fell -15m left. Having fitness effectively 'unclamped' while being mechanically bound between 0 and 1 by the nature of the formula itself anyway, I believe would also incentivize constant improvement at the task; currently, if fitness does reach 100% at any task then no further improvement seems to be expressly selected even if the body still has more potential that several creatures go effectively unrewarded for tapping into.