In the Japanese version, there is an optional sidequest accessible by linking Lunar Knights with Mega Man Star Force through WiFi and entering a modified version of the Konami Code. This side quest is unavailable in all international versions.

In the prototype of Mega Man Star Force, Geo had a different mugshot, however, the likeness of this mugshot is used in another game. Like the Battle Network games before it, Star Force has a crossover feature with Lunar Knights, a spiritual successor to the Boktai series. In Lunar Knights, Geo's mugshot resembles the one found in the prototype. The Mega Man sprite, however, is much closer to Star Force's final mugshot.