  A potentialist system is a first-order Kripke model based on embeddings. I
define the notion of bisimulation for these systems, and provide a number of
examples. Given a first-order theory $T$, the system $\mathrm{Mod}(T)$ consists
of all models of $T$. We can then take either all embeddings, or all
substructure inclusions, between these models. I show that these two ways of
defining $\mathrm{Mod}(T)$ are bitotally bisimilar. Next, I relate the notion
of bisimulation to a generalisation of the Ehrenfeucht-Fra\"is\'e game, and use
this to show the equivalence of the existence of a bisimulation with elementary
equivalence with respect to an infinitary language. Finally, I consider the
question of when a potentialist system is bitotally bisimilar to a system
containing set-many models, providing too different sufficient conditions.
