Galaxia (called GALAXIA.WAD (The Ultimate Czech Level) in its text file) is a PWAD created by Pavel Hodek. As part of their 10 Years of Doom feature, Doomworld named it one of the ten best WADs of 1994.
It is notable for an extensive storyline (presented in a separate file, STORY.TXT) which serves as the basis of the WAD's design and progression, in an era when most designers did not care about story or theme. It also features a few new sound effects and two replacement music tracks.
Galaxia's protagonist is one of two astronauts whose ship has fallen through a wormhole, emerging irretrievably far from Earth. Finding an apparently inhabited planet nearby, they descend in a small scout craft to investigate, but are attacked by a giant insect and forced to crash land. It turns out that indigenous humanoids have been driven from their surface dwellings by an invasion of giant spiders. The protagonists decide to supply the humanoids with weaponry from their ship. The encampment is assaulted by insects and the player must traverse a huge underground complex to return to the scout craft.
In the epilogue, the player suddenly learns that teleportation technology is known to the spider race, as a few of the enemy soldiers have reached the orbiting ship ahead of him.
Galaxia contains two levels, replacing E1M1 and E1M9. E1M1 is where the majority of the action is set; E1M9 is intended as a short epilogue and is meant to be played from scratch.
This WAD includes a demo of E1M9, replacing the third built-in demo. Although small, E1M9 is fully playable, and would have easily fit within the constraints of later Congestion megawads, such as Congestion 1024.