Thanks for the feedback! Yea, I was worried about the engine sound being a bit raucous, especially when a bunch of karts are next to each other at the beginning of the race. All karts start with the same speed. Gems picked up during the race make a kart faster. The AI is a little dumb and a bit greedy when it comes to collecting gems. Capitalize on that greed and you will overtake them, but don't forget to keep picking up gems--they are more substantial than coins in Mario Kart.