In the paper, we describe selected functionality of the current version of a new software tool, called PhysarumSoft, developed for programming Physarum machines and simulating Physarum games. The tool was designed for the Java platform. A Physarum machine is a biological computing device implemented in the plasmodium of Physarum polycephalum or Badhamia utricularis that are one-cell organisms able to build programmable complex networks. The plasmodial stage of such organisms is a natural transition system that can be used as a medium for solving different computational tasks as well as creating bio-inspired strategy games.