This hot air engine is slightly unusual in a few ways. The most obvious is that the crankshaft axis is vertical, putting the flywheel in a horizontal plane. Less obvious is that there is no visible connection to the displacer piston, neither mechanical or magnetic. I'm not sure, but I assume the motion of the displacer is controlled by the pressure variation in the cylinder. There is also a speed control, which consists of a needle valve between the displacer and power cylinder.
The displacer piston and cylinder are glass, the piston being free in the cylinder. The displacement piston is approx. 13mm diameter with a stroke of only about 5mm. It is heated by a small glass wick type meths burner. Between the displacer and the power cylinder there is a needle valve to control speed, and a long metal pipe, which must act, to a certain extent, as a heat storage and regenerator. This justifies the classification as a Stirling cycle engine.
The power cylinder is glass inside a metal casing. The piston also appears to be glass, 9mm diameter with a stroke of 8mm. The piston rod connects to a disk crank on the crankshaft. The disk has the appearance of a gear wheel, although this is probably more decorative than functional. The crankshaft is oriented vertically, supported by ball bearings (I think). It has a 60mm diameter flywheel. Due to the indirect coupling of the displacer, the crankshaft will rotate in either direction, according to how it is started.
The whole is mounted on a square wooden base.