The PCB includes four motor drivers, giving users the flexibility to drive the robot how they see fit. You could, for example, keep it simple and attach one motor per wheel. Or you could take advantage of the ability to control each wheel and opt for mecanum-style wheels. Or you could choose to add one motor per side to control two wheels, freeing up the other two motor drivers for google eyes, gun turrets, or whatever else you want – the choice is yours.
We like this project, and not just because it’s by one of our favourite humans (and the author of our KiCad PCB design tutorial series). We like it because, even though it’s cheap, it’s got loads of potential for experimentation.