Hi David!
I tested your track and I am quite impressed. This track radically follows the comic style guideline. I like it.
Here are some suggestions on how to improve it:
The cars/ other obstacles are placed such that they simply make the road more narrow. But once you know that you simply have to follow the middle line of the road, this part of the track lost its challange. I could even manage to get past all obstacles although my vision was blocked by a plunger. You could arrange the cars such that the karts are forced to drive in curves to avoid them.
Here suddenly the middle stripes end. Why?
I like the falling rocks - once I learned how to avoid them. (By driving as far left as possible.)
This part of the track needs some visual improvements. Both the road and the sky have almost the same color.
I like this part of the track. It somehow reminds me of the android game "subway surfers". But why is the sequence with the trains so short? There is still some room left to extend this part of the track.
And by the way: in subway surfers there are ramps that allow the player to climb on top of the trains. This could be a cool feature if done well. (The ramps have to be easier to use than the ramps in oliver's math class!)
This screenshot shows an animated engine. I guess you invested some time to create this detail. Make it more visible - the players can see this part only for a fraction of a second.
By the way - the blue factory needs more details. I does not even have windows.
Keep up your good work.
And upload your tracks to the addons - they are worth it.