Noctis is a computer space flight simulator featuring first-person visual exploration of an imaginary galaxy.

The player is manifested in Noctis as the pilot of spacecraft called a Stardrifter, capable of instantaneous interstellar travel. This allows travelling between stars, refuelling the Stardrifter from Lithium ion-ejecting stars, approaching planets in star systems and their moons, and even landing where it is physically possible. Many planets feature atmospheres and weather effects. Some harbour plants and animals, or even mysterious ruins. No goal or measure of success is imposed by the game: it simply allows the player to catalogue and annotate the player's discoveries in a common database of stellar bodies called the GUIDE, which is to be synchronised over the author's Internet server.