When you first arrived on this island, some few years ago, your surrogate mother provided you with a small room which she had previously used to store her collection of Mew Mew Life-Sized Mew Mew Dolls Extravagananza tm. boxes. Now to explain the previous statement, as you know, the anime "Mew Mew's Bizzar adventure: friendship is magic KDX" is the current run of the tv show series, "Mew Mew" in which a young girl has a bunch of friends or something, I don't remember because I usually am speedrunning by that point, so my finger is on the button to skip the dialogue. Anyways, the production company behind that show and the rest of the series has a line of merchandise for the super fans of Mew Mew. The line is a series of dolls that are lifelike replicas of Mew Mew that people could do whatever the pleased with them. Your mother, upon escaping the underground, after learning of Mew Mew's total nicheness, bought several hundred of these dolls. These dolls need a lot of packaging, and Alphys didn't want to throw away the box, so, she used your as-of-then empty room to store those boxes.
Then, when you moved in, she had to relocate the boxes into a room that had just been discovered in the frog statue on the island. Then, after several complaints of the size of your room, your mother expanded your original floor, then added two whole other floors. I will now explain the purposes of each floor.
Your bottom floor is a relaxation floor. It contains your television, computer, other forms of entertainment and a full-on spa. The spa itself works via electric diodes which dot the room (similar to the Vr system lightboxes), which sends electric signals through the air, which forces atoms to react in a way that acts like it is massaging you, which it feels exactly like that, heat and all.
Your mid floor pertains to your sleeping quarters, your 3-acre virtual closet, and of course, your performance stage. Your top floor contains your swimming pool, along with a full-scale laser-tag which doubles as a spy training course.