Easter Eggs

In the debug builds of the game, YandereDev has included some Easter eggs. These are usually added when Dev does not have enough time to write code for the game. They include wearable accessories for Yandere-chan, game modes, a small timed event at the starting menu, and a transparent figure/phantom. The final game will have cheat codes that change the appearance of the characters, like the Easter Eggs do.

Accessories

 * "H" key to cycle through hairstyles.
 * Her default hair; which is a Ponytail
 * Right-sided Ponytail
 * Left-sided Ponytail
 * Pigtails
 * Three Ponytails
 * Longer Pigtails (known as Twintails)
 * Drill-hair
 * Long hair
 * Very long hair
 * Rei Ayanami's hair (Neon Genesis Evangelion)
 * Yuno Gasai's hair (Mirai Nikki)
 * Korra's hair (Legend of Korra)
 * Short blonde hair (Galo Sengen)
 * Hatred Mode hair
 * Bald with Barcode (Hitman)

Modes

 * By using the "?" key, you will see the "Easter Egg Menu". This shows the following options:
 * "P" key to activate "Punished Mode". This mode cannot be deactivated until you reset the game. This mode is a reference to the game Metal Gear Solid 5. It gives Yandere-chan a torn-up school outfit, a tan-colored scarf, a black eyepatch on her right eye, a red left arm, a scar on her left eye, a black protrusion from her forehead, a black glove on her right hand, and a cigar. It also replaces the music with "Nuclear" by Mike Oldfield.
 * "X" key to activate "Slender Mode". This mode makes Yandere-chan's uniform turn black/gray, her skin will turn completely white, make her eyes blank, she will be bald, and her body shape will resemble that of Slenderman's. Suspenseful music plays the whole time while in this mode. This will cause other students to treat Yandere-chan just as if she were insane, and being noticed by Senpai or by a teacher will result in game over. Activating this mode sets Yandere-chan to minimal sanity level. As such, if you encounter Senpai in this mode, it will result in a Heartbroken screen or an Expelled screen if you encounter a Teacher in this mode. The weapon she chooses becomes larger. You can still laugh to gain sanity in this mode.
 * "B" key to activate "Bancho Mode". The mode cannot be deactivated until you reset the game. This gives Yandere-chan's bandaged arms, a black school outfit, a Sargent cap, and a pick in her mouth. The music playing in this mode is "BafBaf! Sonna ni Moeru no ga...Suki Kai" by Iwasaki Taku. This mode is a reference to Mako's Two-Star Goku Uniform from the anime Kill la Kill.
 * "H" key to activate "Hateful Mode". The mode cannot be deactivated until you reset the game. It's is a reference to the game Hatred. Yandere-Chan's uniform will turn into a blackish-gray, and the atmosphere will turn red. As with Slenderman mode, this will set the sanity level to minimum. Metal music plays the whole time in this mode. As such, if you encounter Senpai in this mode, it will result in a Heartbroken screen or an Expelled screen if you encounter a Teacher in this mode. There is a glitch where if you have the August 12th build, while Hateful Mode is active and the player changes Yandere-chan's clothing to Nude, School Swimsuit, or Gym Uniform, Yandere-chan gets stretched.
 * "S" key to activate "Spooky Mode". This mode turns all female students and teachers into skeletons and plays the song "Spooky, Scary Skeletons" by Andrew Gold in the background. While the female students and teachers are skeletons, their bangs seem to disappear. The reason the male students are not skeletons could be that the player would not be able to tell them apart. The Nurse and Osana Najimi do not turn into skeletons.
 * "T" key to activate "Titan Mode". This mode cannot be deactivated until you reset the game. This mode is a reference to the anime Attack on Titan, or Shingeki no Kyojin. It will make the students increase greatly in size and remove their clothing. It will also make Yandere-chan's uniform partially brown instead of blue. Pressing the "L" and "K" key rapidly in this mode will make Senpai and the teachers titans as well.
 * "G" key to activate "Galo Mode". This mode cannot be deactivated until you reset the game. It gives Yandere-chan tanned skin, gold bracelets, sunglasses and super saiyan hair. It also replaces the music with "Galo Sengen" by Policeman. Pressing the Ctrl button will make Yandere-chan "power up". Your reputation will not be affected if you laugh insanely.
 * "K" key to activate "DK Mode". This mode will make Yandere-Chan's and all the students' (including Senpai) head and arms large. This is a reference to a cheat of the same name and function from GoldenEye007. You cannot use your camera because your massive head obscures the camera. Pink thingc.png
 * "L" key to activate "47 Mode". This mode will make Yandere-Chan bald, have a barcode on the back of her head, and change her shirt to a black jacket with a red bow. The music is replaced by "Only You Can Stop Them" by Jesper Kyd from the game Hitman - Blood Money. This mode is a reference to the game Hitman.
 * "J" key to activate "Bad Romance". Bad Romance is a Stand for Yandere-chan's protection. This mode is a reference to the anime JoJo's Bizarre Adventure. The Stand is named after the song "Bad Romance" by Lady GaGa. Bad Romance can hold up to 8 weapons. The name could change later on, but this is what YandereDev is thinking about. This Easter Egg can only be activated on the Easter Egg menu, even though it doesn't show. BR currently does not do anything, so it might still be a work in progress. Bad Romance was also inspired by a piece of fanart. The mask of Bad Romance can be seen on the left side of Akademi High School's wall.
 * "N" key to remove clothes. Pressing N with the Easter egg menu open will make Yandere-chan naked. It does not show up on the menu.

Phantom Girl
If you take a picture in the bathroom on the 3rd floor, a semi-transparent girl about half the size of an average student model will appear in the picture. No matter where Yandere-chan is the ghost will be looking in her direction.

This character will be known to move throughout the game, as she used to be behind the single cherry blossom tree behind the school. If you ran into her, your uniform changed into red and black. The outfit change was later removed because many people claimed it was a bug.

Starting screen
After about 10 seconds, the screen title will show the darker side of the game for a short amount of time, this including a dark atmosphere, a bloody uniform, and squirming corpses. Pressing the space bar can manually change to the "insane" title screen, but only for a short amount of time as well.

You can make the "insane" title screen last longer by repeatedly tapping the space bar.

In an older version, the starting screen had different animations every ten seconds such as Yandere-chan stabbing a student rapidly, being covered in blood while carrying a severed head, and staring blankly at the viewer. The only music played during these scenes are static.

April Fools
For April Fools 2015 YandereDev released Super Yandere 64 and Kuudere Simulator.

Super Yandere 64
This game is a Super Mario 64 remake in Unity with Yandere-chan instead of Mario.

Kuudere Simulator
Kuudere Simulator is the opposite of Yandere Simulator. The main character doesn't want a Senpai and sits on a chair inside of a room. There is also an option that lets players activate a Tsundere Mode, which causes Kuudere-chan to switch to her alter ego, Tsundere-chan. If done right, she'll say the word "Baka" at the push of a button.



Bugs

 * Titan students run into walls, get stuck, and usually move backwards.
 * When a Titan is killed through whatever means, the ragdoll base collapses in on itself, and the body turns into a ball of flesh and rolls all over the place. YandereDev has stated that the bug is too humorous to fix.
 * Some decoration Easter Eggs obstruct the camera view.

Trivia

 * There used to be a bug that was patched where if you went into Hatred Mode and changed in the Shower Room, your entire body would warp into a terrifying inhuman figure. SWEETJESUS.png
 * Pippi Osu ,Midori Gurin and Ryuto Ippongo themselves are Easter Eggs. Pippi is from a game called Osu!, Midori is based on the character Churuya-san from The Melancholy of Haruhi Suzumiya and Ryuto is the original mascot from the game Osu.
 * Many current easter eggs contain copyrighted music. Eventually all copyright music in Yandere Simulator will have to be replaced with composed original sound alike music. If nobody volunteers to compose replacement music or if there is no budget to do so, then the Easter Eggs would have to be removed from the game entirely. If people still want the Easter Eggs, then YandereDev said he would keep the silly costumes in the game but no music at all.