It's the tallest construction in the city and Dorothy's headquarters. It's guarded by masked soldiers outside, and by Rabbits, Armed Security and Arabesque inside. This is also the only stage in Galerians where the player will encounter the second form of Arabesque.
Dorothy's tower is a vertical structure with several floors and no stairs and can be reached only through elevator shooters although most of them are inactivate. Each floor has several of them especially the ground floor, which also has at the center a large round area that's able to teleport someone to a room that controls the elevators via a color code system. The highest floor in all white before the summit has multiple large windows which offer a view of the city below.
The summit itself contains the Hand of God Area, where there are five giant statues including incubators for each one of the first Galerians. It's unknown if they were born here or if they were simply sleeping before being released. The only door in this red room is connected with a bridge that connects to a single save point in a dark room. After the battle with Cain, this room is revealed to be Dorothy's chamber.
After having effortlessly defeated the masked soldiers, the two get separated when Lilia is teleported away. However, in the room she finds herself, Lilia is able to help Rion in reaching the summit with both facing illusions of the three deceased Galerians: Birdman, Rainheart, and Rita. However they also have to fight Cain, Rion's twin brother, who reveals to them the Rion's true nature. When he is dead, the two teenagers fight Dorothy, ultimately destroying her, as well as blowing a hole through the top of the tower itself.
In the sequel Galerians: Ash, it is revealed Lilia put Rion's body in cryogenic storage and that the Mushroom Tower also contained the backup of Dorothy's data including information about Family Program, Ash and the Last Galerians, as well as a connection to a virtual digital world.
Six years later, Lilia discovers that Rion is in the back-up data at Mushroom Tower and she requests military's help in bypassing the security's locks and eventually she recovers Rion's data.
A version of the Mushroom Tower appears in Galerians: Ash but it's much more expanded compared to the Mushroom Tower in the first game. It's a virtual version of the Dome Area that is not explored in the first game. The Hand of God (called now the Family Program Room) has it's door connecting to the Dome Area and Dorothy's Chamber itself lies at the center of it. The Dome Area also contains four security areas, one for each cardinal point: N,W,E and S. Using several computers, these areas can be rotated and connected using an elevator to three areas called Last Galerians R&D Area 1,2 and 3. The third can be connected to Security Area S, the second to Security Area W, and the first to both Security Area N and E. Each Last Galerians R&D Area can be connected to a bridge conducting to Dorothy's Chamber, but the last one can be connected using its computer only to Area 1. Each Last Galerians R&D Area hold computer terminals that have development data for Ash, the main antagonist of Galerians: Ash. The third is connected to General System Area Alpha, which is protected by walls of energy, the second to General System Area Beta, protected by red lasers. The first secretly contains the terminal under the floor and is connected to the LG Programming Room, which has a connection to Ash's data that can be reached also in Uranium Refinery. The computer terminals can only be accessed with Ash's passwords: Anger, Sadness, and Hate.
Rion is trapped in this virtual world for six years, believing he is still fighting Dorothy, defeating her again and again, without being able to end the circle. When Lilia is able to contact him, he starts to doubt about his status. He is attacked by the Last Galerian Spider, arriving to delete his data, but he is able to win while his opponent retreated and warned him that the outside world is a dangerous place. Defeating Dorothy one last time, he is finally able to escape to the real world.
He returns after having realized Ash is planning to resurrect Dorothy, downloading her data. He discovers a computer which contains information about his enemy, but he is unable to hack it. When Lilia asks him to return to real world, he faced and defeated the Last Galerian Nitro and leaves the virtual world.
When he return there again later, he fights and defeats for the second time Spider who while dying tells him there are two other computers with important information regarding Ash. Before Rion can return to the real world again, he is trapped by Nitro in an illusion, but he is able to counterattack and kill her. He once again leaves the data world.
Returning one last time to the virtual Mushroom Tower, he then gains access to the other two computers, discovering Ash's true identity as an A.I. When the Last Galerian resurrects Dorothy, imprisoning her as a slave program in the process, he challenges Rion to stop him. Rion returns to real world again and eventually returns to Ash's data at the Uranium Refinery.
- Mushroom Tower is the shortest stage in Galerians. This not including the data world version in the sequel, which is an expanded version of the Dome Area at the top. It can be considered the only location which appears in both games.
- This area is similar to Mount Olympus as it's an imposing mountain summit that is inhabited by the Greek God Zeus and in Galerians by Dorothy. It is also similar to the mountain of purgatory in Dante's Purgatory, which must be climbed by the protagonist in order to reach God at the summit. However, unlike the description of the Christian God, Dorothy is depicted in the story as an evil being.