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)
One last thing I should mention is that this game offers multiple difficulty levels. (rpgfan.com)
Multiple difficulty levels reward investment and mastery, and then you can take all of those skills and use them to beat up your friends next time you have people around. (pcgamer.com)