Terrain does impact the challenge! Grass tiles have easier challenges than mountains and forests. You probably landed on a mountain tile for your first encounter and got a rare result. We were planning to do more with this (for example, mountains and forests would have gauntlets of challenges, so you'd want to stay on grass while outrunning winter) but ran out of time!
The mouse controls show you the range of movement, but the keyboard controls do not. Great feedback, thank you!