|1 - 99||100 - 199||200 - 299||300 - 399||400 - 499||500 - 599||600 - 699||700 - 799||800 - 899||900 - 1000|
The room on the right is a hallway full of glass tanks with creepy "subjects" inside, one of which is broken and the creature inside missing. Here, the player finds a note reporting the difficulty of containing "Subject 5" due to the lack of sedatives. After obtaining the key card here, the player continues to the next room. Inside, the Generic Lab Assistant's last report can be found, next to a bloodstain on the floor, which states that Subject 5 (Specimen 3) has escaped and that they can hear a clicking noise getting louder. After walking into the hall ahead, a clicking sound is heard, and Specimen 3 gives chase.
Once the player reaches Room 150, they will find an elevator with a save point.
Specimens 1, 2, or 3 can return to keep the player on their toes until they reach Room 165 (160-167 in the HD Renovation): the abandoned Japanese school.
The atmosphere changes drastically, and the player now carries a flashlight. In the classrooms, shadow figures stand idle and will hurt the player if touched. They are only visible when the player shines the flashlight on them. Notes are spread around on the different desks. They talk about a ghost who eats tardy children, including a child called Matsuri. Upon getting to the exit, Specimen 4 appears behind the player and the chase starts. Specimen 4 is not visible in Room 165 unless the player shines the flashlight on her. Otherwise, she's always visible.
In the HD Renovation, after Room 161, the school rooms are randomly generated until Room 167, where Specimen 4's chase starts. The flashlight effect with Specimen 4 is not present.
When the player reaches Room 200, they will find an elevator with a save point again.
- The GL Labs area is probably a reference to the horror game SCP - Containment Breach. The keycard has "Class B" written on it, which resembles the game's system of numbering keycards.
- In some of the classrooms of the abandoned school area, there is a poster of the character Kyubey from the anime Puella Magi Madoka Magica, and in the same area, there are pencil doodles of anime characters next to some chalkboards. One appears to be the Vocaloid character Hatsune Miku.
- There's also a poster resembling the cover art from Doom 1.
- At first, the post-it notes in one of the classrooms seem innocent, with "ネコ", "犬", "魚" and "バグ" meaning "cat", "dog", "fish", and "bug", respectively. "悪の傷", however, roughly translates into something along the lines of "evil wounds".
- A poster in one of the classrooms of Room 165 (161 in the HD Renovation) says the following: "学校 教育は教育なしに私たちはすべてのクジラ、うめき声出血クジラが、何もあり、重要です。私は男に来る意味。" The translation is most likely gibberish, but would roughly translate to "School - We, in a school without schooling, are all whales, moaning, bleeding whales, and it is essential that is all we are. I am the meaning that will come to men."
- The rooms 100-199 are the only hundred rooms with two specimens in them: Specimen 3 and Specimen 4.
- In one of the Japanese classrooms, a drawing of some anime-like girls sits on the wall. The girl in the middle of the top row bears a resemblance to Paina, a 'secret' specimen that can be found through a special easter egg.