How does the Super Awesome Micro Project work?
Assuming that you're asking about the engine in particular, it seems to be a large number of pneumatic engines that have been coupled together in order to supply the required torque. LEGO pneumatic engines typically consist of a pneumatic cylinder driving a crankshaft. Here's a basic picture to give you an idea:



The shaft usually also controls a pneumatic valve that switches the direction of the piston to allow continuous rotation as shown here:



This allows the engine to run on air pressure being directed to the pneumatic valve without the use of any electrical components.

These images come from a fairly simple single cylinder pneumatic engine by nico71 on Rebrickable that includes instructions if you are curious about more of the details of how these work, or if you would like to build your own.