If more than 20 controls are visited, the right column unfortunately runs out of space and further times aren't displayed. Hit ESC to abort replay. The most difficult thing is to get used to map scale. On a difficult course you should get only lost if attempting to run full speed all the time. It is easier to run trees off, but certainly not as fun.
Any organized race is supposed to be run trees on.
Copying it to your friends is both legal and recommended. There is a slight chance I might write more advanced versions some day. If you like the game a lot, you may donate more. If you in the other hand are very poor, you might pay less. And feel free to use the currency of your country.