First of all, congratulations for the endurance on this project.
The exe supplied with project does not work on my pc. I was however able to launch the jar directly.
As a hint, it took me a while to figure out why my car is not moving. Luckily i found the help window. Maybe a small hint to press F1 for help would be nice 
I have not found out how to race or where the garage menu shows up, or how to attach the trailer or how to get a job. So i guess i would need some hints
Some tweaks that should be fairly simple to implement:
- Set the camera near plane closer then the radius of the player capsule to eliminate some of the clipping.
- The camera angle is a bit too steep for my tasting (but that could be by design)