To note I have experience making games, but in the past I used GMS2. z coordinates in unity I think are partly the culprit for the weird ground lines. The controls are convoluted somewhat on purpose, I wanted to replicate a retro game feel with also an oddly realistic physics for the bike (Didn't come out right in some ways like how you can just keep going faster until practically light speed). Backgrounds, yea since I was just activating and deactivating there was no transitioning, which should have been present. As for the window, did you make it full screen? I think the game is kinda hard to play without. I blame not having enough time with my schedule!