Aside from the online races, there is a circuit / single player mode to race against AI with multiple difficulty levels, so there is no shortage of content for you to enjoy. (thedgcast.com)
The game isn't really that difficult if you just play on the normal difficulty setting while you have the option of multiple difficulty settings, there isn't much of a replay value. (gearnuke.com)
Still, once you get to it there will be lots of fun to be had with multiple difficulty levels and score competition. (quartertothree.com)