This might be a strange suggestion, but hear me out... Do not count the first 2-3 seconds in each generation. The reason why? Because each creature is slightly slower because they have to get into position to move, since creature design that the creature spawns in isn't exactly the optimal starting position. For example, who would be faster? A human who started in a running stance, or a human who is started in a sitting position? The reason why I think this should be implemented is because you can basically make any creature faster by a large amount just by increasing the evolution time, and by not counting the first 2-3 seconds of prep time, we would have a more accurate view of the creature's actual speed.