I just tried this on real hardware via Harmony. Works great and is just a fantastic work, though a few things were noticed.
The enemy cars become very difficult to see when two or more (or so, just going off what I believe the numbers were) are on screen or with a rock due to the flicker. Perhaps make the enemies a darker color or background lighter to be seen better?
After death from anything, the screen rolls once while drawing the screen. It's a bit bothersome could be gotten used to after a while.
The second track is a little hard to see with the red and orange, along with the flickering enemies. Again, perhaps lighter background or darker walls?
Just what I found, note that I am no programmer. WIll be checking back for updates!