More than a hundred years ago, Dr Josef V. Agon disappeared while working on the mystical powers of the human mind. His Victorian mansion was left undisturbed, until one day you discover the iron gate opened. You enter the mansion and discover Dr Agon's research notes and a strange machine named the Eidolon. After reading the notes, you find out the Eidolon is a travelling machine, capable of transporting its pilot to strange mystical dimensions. You feel a sudden desire to start the machine...
The Eidolon is an arcade exploration game. The player pilots the machine in caves, collecting jewels and energy balls and looking for the dragon guarding the entry to the next level. The Eidolon can shoot four different energy balls: red balls are the most destructive, green balls transform a monster into a different one, blue balls stop time (freezing the target for a few seconds) and yellow balls heal. Shooting costs energy, so the player must pick up gold balls to replenish the machine's reserves. Jewels are needed to breach the energy barrier preventing access to the dragon; there are three on each level, each guarded by a different creature.
The game uses fractal algorithms to create the real-time 3D display of the cave environment.