Add a time-trial option!
This game was basically a Mariokart game. One thing missing, or at least I didn't see it was a time-trial option. This is something some people like to do after beating the game for the thousandth time. Also the missile seems a bit overpowered. Knocking a character into the air and then basically allowing all the other karts to overtake that character unless that character was way too far ahead.