From publisher blurb: Iridescent Space is a complete science fiction RPG of interplanetary adventure. Compatible with the Transdimensional Adventures rules system, Iridescent Space uses a rules medium d20 game system and includes everything needed to play a campaign set in the war-ravaged Talireen Nebula setting (first introduced in the Transdimensional World Book). Includes 14 major species ranging from near-human to entirely alien (lobster-like, octopoid, multi-armed or plant-based) as well as species creation system and rules for mutants based on the various species; space combat system; maps for the sector and major planet descriptions. The class/skill system includes 13 basic classes that are skill packages roughly similar to e.g. a 5E D&D "background", with customizable character creation and compatibility with the full Transdimensional Adventures and Apocalypse Essentials rules. Includes psionics and cybernetics rules.