Ok I got to play it! There's still something weird with the steering: as soon as I press the right trigger, I can't properly turn anymore.
I see a lot of potential here. The premise is great but while playing I was picturing a game where you would do turns around a circuit and have to pass through areas to plant or harvest wheat while trying to beat a time. In the state of your game, I could not go fast since every turn is 90° (if not 180) :/ In the end I was always going slow to get to be precise and would never enjoy the full speed potential of my tractor :( Maybe I didn't get it and it was not about speed, though!
Other than that, it is now working pretty well. Without the steering thing, I think the driving would great. The ambiance is fun and the graphics are working along with the global amiance of the game. Having a variety of levels is a plus. Very well done for a 2 weeks worth amount of work for 2 people!