It's fully interactive so you can try time dependent perturbation theory with you as the perturber.
It uses a numerical solver that does half of the work in the Fourier domain. It's quite stable and guarantees unitarity to machine precision for a good period of time.
Messing about interactively with the parameters will eventually feed high frequency components of the wavefunction to the point where they can no longer be represented faithfully on the discrete grid.