First problem I found is you can't edit the front slope, which means I can't use the software for my current project (a wall halfway up a slope). As I understand it, having a front slope drastically reduces your passive resistance and affects the solution. 

Second item is more of a "it would be nice to have this". I see that there is only 2 soil layers (backfill vs founding soil) and the change is assumed to occur at the base of the cut face. It would be nice to have the analysis capable of 2+ soil layers at varying height.