1. Yes. :-)
5. I also noticed you can point that traffic light in the opposite direction, and still get the same scores.
Another thought:
It's really hard to see the differernce in colour between the red and purple cars/flags (on my monitor, at least).
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ON CRASHY-NESS:
People don't like change, and crashy-ness is a fundamental part of gameplay. When I played v0.21, I initially thought the cars weren't crashy enough, but only because I was used to v0.15. After playing all the levels I changed my mind.
So, I think crashy-ness should be set at whatever level allows for the most interesting/varied/challenging maps. For example, I love TANGLE because there's no single obvious solution, and lots of layouts get scores without gridlock. :-D