Illbleed is a survival horror video game for the Sega Dreamcast. In it, players are tasked with guiding horror movie aficionado Eriko Christy through a deadly theme park riddled with booby-traps and monsters, relying on a heartbeat monitor and her own senses (some of which are conveyed through an in-game interface and others indirectly) to avoid being frightened to death. Should she make it out alive, the eccentric genius responsible for the park's creation, Michael Reynolds, will reward Eriko with a hundred million dollar prize and allow her to leave the amusement park.
The gameplay of Illbleed differs from other survival horror games. The player is encouraged to not rush through the level, but to slowly walk from place to place, looking around and at the environment. Using a tool named the Horror Monitor that consumes the player's adrenaline, the player can mark various places suspected of being a trap. These traps burn, slice, scare, and hit the player in various different ways, resulting in blood loss, rise of pulse, and lowered stamina.
Initially, the player may only choose Eriko. As the player rescues each of Eriko's friends, the player has more choices of characters to play with. After beating the game for the first time, Eriko will wear less clothing for each character she fails to rescue in future playthroughs.
The opening scene in Illbleed starts with the main character, Eriko, giving a speech for a 12th grade speech contest. She talks about her troubled childhood in which her father, who was a horror theme park designer, tested out all his new traps and props on her until she was six years old, when her mother left him. At age seven, Eriko only watched many different horror movies and then later, at high school, she created the "Horror Movie Research Club" with her as the club president. All of Eriko's friends are members of the club (with the expection of Jorg, who they meet much later in the game).
They beg Eriko to go with them, but Eriko remains unimpressed and is certain that the park is just a hoax with cheap props and scares. Smitten with the idea of victory, Kevin, Michel, and Randy all set out for Illbleed and leave Eriko with her ticket.
After the player completes all the levels, he/she is forced to venture into the "Michael Reynolds' Horror Museum." He/She fights one of three bosses that Michael (the creator of the theme park) has set up for them in order to complete the game. The number of friends saved will determine the ending of the game.
If the player finishes the game a second time, and does not save anyone, the true ending is shown. Eriko finds out that the mastermind behind Illbleed, Michael Reynolds, is actually her father Reynolds reveals that his true intention is solely to scare Eriko after being unable to do so when she turned six. A fight ensues with Eriko emerging as the victor and commenting on how Reynolds "destroyed himself" and "scared the living hell out of her".