From the Introduction:
GEPTOREM is the third in a series of adventures to alien worlds, approved for use with Traveller™. It was designed as an adventure for characters as a part of a larger campaign or as an evening's entertainment. The charts given are guidelines, so the referee should feel free to add to or delete as he sees fit. Above all, remember role-playing is free form, so change what you want, add what you wish or play as is... just have fun!
Nystalux uses Basic Traveller with references to Mercenary & High Guard.
The setting is non-canon. Includes a large full color world hex map.