Of course you have new enemies from the campaign as well as bonus rounds, where if you say kill enemies a certain way you will get a money bonus. (gamingbolt.com)
You can also face the other racers in special bonus rounds where they will do their best to let you eat their dust... or bubbles. (darkainarts.com)
There are three bonus rounds which are more fun than the game fighting part of the game. (thezombiechimp.com)