The applet will display both the wavefunction and the Bloch function, but students might not see immediately the distinction, and in some views there is no difference.
This applet only allows periodic potentials, so that it can't be used to study "impurities". This capability is available in a different applet by the same author for a finite array of wells.
There is no indication of the algorithm and physics used in this simulation to compute the states and the time dependence.
There are links to reference material from the Wikipeadia for terms used in the instructions for the simulation. Instructors may wish to check these references before assigning the simulation to students.