Like many other computer games, the player can use both the arrow keys or 'WASD' to navigate through the rooms. However, holding down a movement key while going through a door will not result in the player's continued motion; the player will simply stop, and must press and hold the key once again to continue moving.
Holding the Shift key allows the player to sprint until their stamina bar is depleted, or until they release Shift. At first, this function is most useful for getting through rooms faster, but later in the game, it becomes necessary to escape the mansion's many deadly enemies.
Along with the sprint button, a technique known as "strafing" is present. Instead of going in a straight path, the player holds down the up/down and right/left keys simultaneously.
Starting at Room 750, sprinting is replaced with the dysfunctional and cheap "Infinite Stamina", which removes the sprint function entirely, and is considered to be a "gift" by Spooky. However, the player will be able to sprint once they pass through 15 rooms.
The player can use the Spacebar or E key to interact with their surroundings, and perform actions such as viewing notes, opening doors/vents, picking up items or hiding.
Pressing the E key on one of the purple crosses found throughout the game will allow the player to save.
Saving is possible after every increment of 50 rooms. However, starting on Room 300, each saving point is separated by 100 rooms.
Saving is also possible at rooms 250, 500 and 750, with each containing a plate showing the password for the respective milestone room.
In the Karamari Hospital DLC, saving is possible by using the water fountain in the waiting room, causing the screen to briefly turn red.
In Endless Mode, there are no passwords, and Rooms 250 and 750 are no longer save points. Additionally, once the player reaches Room 1000, save points only appear once every 200 rooms.
There are three options to leave the game:
- Press [Esc] + choose "Exit"
- Press Alt + F4
- Main Menu
Pressing F9 will have the game take a screenshot, which is a very useful mechanic for getting images of the game. The screenshots will be saved in the game files.
On the Steam version, pressing F12 also takes a screenshot.
In the options menu, it is possible to skip directly to room 250, 500, or 750 if the player knows the respective password.
The passwords show up above the save point in their respective rooms.
- Room 250: 'PUMPKIN'
- Room 500: 'CHEESE'
- Room 750: 'CAKE'
Pressing 'Backspace' or 'Esc' pauses the game.
Main article: Axe
The Axe is the only weapon in the base game. The axe is swung by pressing the left mouse button. Its main uses are to kill violent deer, open blocked doors (including the Exit doors) and kill Specimen 9's boss form.
It will also allow the player to stun or kill certain other enemies. The axe will cut down Specimen 1 instances and knock back Specimen 2. Specimen 3 will be stunned for 1-2 seconds when hit. Specimen 6 will be knocked out and rendered harmless, but only for one room, and will return when the player enters the next room. Specimen 10 cannot be hurt with the axe, and instead, it will transform into its much faster 2nd form. Hitting Specimen 11 with the axe simply makes it disappear for one room, though it returns once the player proceeds to the next room.
When out of stamina, swinging speed does not decrease, allowing for "spamming" of the attack button at this time.
- This does not work in HD Renovation; you simply get a noise when you attempt to swing either weapon with insufficient stamina.
In the Endless Mode, the axe can also be used to destroy Spooper (whom blocks doors once it appears) and destroy any of Tirsiak's shadow animals that block the player's path (though the axe is useless against Tirsiak herself).
Main article: Sword
In the Karamari Hospital DLC, another weapon is present. Said weapon is a sword, and can only be obtained in New Game +.
The Sword works identically to the axe, but it also can kill most of the enemies present in the DLC. Like the axe, using it will affect the game's ending.
- The Passwords put together spell out Pumpkin Cheesecake, which is Akuma Kira's favorite October dessert.
- Every time the player presses the Shift key (Sprint), a small amount of the player's stamina gets lost even if the player doesn't move. Repeatedly pressing Shift can make the stamina bar completely empty without moving or using a weapon. This was fixed in HD Renovation.
- If the player loads a saved game, they can use the purple cross to save the game again in the same place.
- At the beginning of Karamari Hospital, there's a purple save cross in the elevator, but it cannot be used.