The damping control is labeled "friction", however the nature of the damping force is not discussed. If it is a velocity-dependent damping, it is probably a little misleading to call it friction. If it is something else, its nature should be explained, since friction resulting from contact between sliding surfaces normally would not be encountered with masses hanging vertically.
The energy graphs have some missing information. It is not clear where the reference level for gravitational potential energy has been located, but it appears to be out of the figure. The zero for elastic potential energy, likewise, does not seem to be quite at the height designated by a dashed line. Finally, the work done by the dissipative force is labeled "heat". Students should be made aware of this connection, and the definition of heat, as this is sometimes not treated at this point in a physics course.
The spring motion is constrained to the vertical direction, but there are no visual clues as to why.