The Dream mode, which is where one would initially spend most of their time, allows you to unlock licensed cars for use in the Arcade mode. Here is where you take the role of manufacturer and driver, first by choosing from several car designs, and then by building and racing the car you hope others will want to buy.
This is really not unlike other racing games, but instead of earning a certain number of points or a certain amount of money, you have to sell a certain number of cars, and the number of cars you sell is directly associated with how you place in races. Once you sell enough cars, you can then choose a new design to build, race, and sell, and this also opens up the licensed version of the car for the Arcade mode.
While this may sound intriguing, and there really isn't anything wrong with the mode, it can be a let down if you were expecting more from Apex. You are not allowed to design your own car, but instead you are allowed to choose a design from several, and that severely limits the possibilities.
The racing itself is not bad, although it definitely doesn't match games like Sega GT 2002, or even The Need for Speed: Hot Pursuit 2. While those games have their own flaws, they seem to hide them better than Apex does. In Apex, cars group together, and if you wreck or otherwise fall behind, you can easily catch up to the grouping, which makes races seem very stilted. This makes it very hard to feel any sense of accomplishment, because no matter how hard you work at winning a race, you will not be able to shake the group, and the group will do everything in its power to wreck you.
Beyond the difficulty of racing effectively, the cars handle oddly, with turning quite different than other games, and down shifting quite difficult to achieve. It is hard to say why developer Milestone chose to model the cars this way, and why they also chose to display visible damage, but not make it affect car handling, but the end effect is a racing game that just doesn't feel quite right.