If you only want to play alone, there are still a few things you can do. The included tracks have benchmarks built in for you to compete against for medals, and if you're not an expert racer the content will take quite a while to unlock. Even getting to the end of some of the Black-level tracks can be a significant challenge, let alone burning through at high enough speeds to earn medals. While the content can be fun to race through, the experience can feel a little lonely with only ghost cars to accompany you. Thankfully there's an option to load in the ghost cars of the replays of other players if you're connected online, which helps promote a sense of competition as well as tip you off to better lines around the tracks.