The game begins with the front of the mansion visible in the background of the title screen, which then proceeds to you encountering Spooky, a small blue ghost. She sarcastically welcomes the player, then lets the player proceed with the game. There are long hallways and twisting passages all throughout the game.
The first monster you encounter, and will continue to encounter, is Specimen 1, a cardboard pop out. The next one ups the ante: Specimen 2, a slimy apparition that can go through walls and attacks the player. After that is Specimen 3, a spider sort of monster constructed of flesh that follows and attacks the player. Specimen 4 is a 14th century spirit with the appearance of a schoolgirl that goes through walls and attacks the player (sensing a theme yet?)
Next is Specimen 5, a faceless humanoid thing that attacks the player with a giant blade and changes the texture on the walls. After that is Specimen 6, a life-sized puppet that attacks the player when they aren't looking at them. Then it's Specimen 7, which is initially a cat that turns into a wall of anatomy symbols that chases you. Then you encounter Specimen 8, which is both a pack of carnivorous deer and a deer apparition that chases the player, saying that it will "feed it's children".
Specimen 9 is a secret. Specimen 10 is a humanoid mound of flesh that releases a leech on the player when they get too far away. Specimen 11 is a demon that floats towards the player quickly and attacks them. Specimen 12 is a mansion-like area that possess a host to kill others (currently a middle aged asian male with a scythe.
Specimen 13 is a mermaid-like monster that travels through the water and hits the player when they go in the water. The boss of the game is none other that Specimen 9! It uses flesh pillars, shadow hands, minions, and fireballs to attack you.
There are currently 2 ending in the game. The "good" ending has the roof fall on the character, killing them and turning them into a ghost, when Spooky recruits them into her army. The "bad" ending of the game has Spooky turning the player into one of her specimens.