'Quatre mains' is a duet where both players share a single piano.

By inserting yourself into a performance that's already begun, you'll just ruin the music and annoy the pianists.

Created in 6 weeks as a submission for EroHorror VN Jam 2025

Butterfly Æffect is a multi-route visual novel inspired by bishoujo games and early 2000s American anime culture about love, lust, spite, violence, and nipping your problems in the bud.

You play as Damien, a freshman at a remote college who dreams of erasing his feelings of inadequacy by finding a girlfriend. Drawn through convenience to two sets of potential love interests, he doesn't realize just how unwelcome his presence is until it's too late.

Part 1 is a nostalgic love letter to the genre, from lovey dovey meetcute CGs to our protagonist’s near-delusional certainty that he can wear any girl down if he tries hard enough.

Part 2 features four standalone endings showing the bloody consequences of that certainty.

• 50k~ total words
• 2 part story, with unique branching conclusions for all 4 love interests
• 6 full CG illustrations, plus 13 cut-in illustrations 
• OST contains 15 original pieces of music in a variety of genres and 50 custom SFX
• 40+ self-sourced custom backgrounds w/ dithering FX done in Adobe After Effects
• No AI tools were used to create Butterfly Æffect

Butterfly Æffect is a mature work of Erotic Horror fiction for players aged 18+ that includes:

Click to expand/collapse CWs (General Spoilers)

• Sexual homicide 
• Gore and mutilation
• Dubious consent
• Strong language
• Underage drinking

In addition, you may encounter the following scenarios (ending dependent):

Click to expand/collapse detailed CWs (Endings Spoilers)

Content warnings for each torture ending are as follows:

Vi

• Awareness under anesthesia
• Graphic descriptions of nerve trauma
• Anaphylaxis 
• Drugging
• Mentions of animal death and self harm
• Suffocation

Ollie

• Traumatic head injury/cognitive impairment
• Graphic descriptions of bodily injury/broken bones
• Extreme petplay
• Mentions of animal death and self harm
• Suffocation

Gabrielle

• Use of pins/needles for torture
• Mutilation of ears
• Strangulation
• Descriptions of insects
• Live entombment

Raine

• Humiliation
• Exhibitionism
• Bondage
• Drugging
• Mutilation of eyes, tongue, and teeth
• Stabbing 

Player discretion is advised.

Director, Programmer, Writer (Raine route) - ALTERLNX

Art director, Sprites Sketches, Torture CGs - Foil

Sound Design, Music, & Arrangement; Additional Art - C.DLX

Writer (Vi Route), Additional Art - saturn

Writer (Gabrielle Route), Lineart, Sprite Expressions - Ophelia

Writer (Ollie Route), UI/Graphic Design - marinakazam!

Backgrounds - nick m

Sprite & CG Colorist, Sprite Expressions - Maxie

Guest Art - evillittlebug

Guest Art & Photography - Beecusp

• Enter - Advance dialogue and activate interface
• Space - Advance dialogue without selecting choice
• Arrow Keys - Navigate interface
• Escape - Access game menu
• Ctrl - Hold to skip dialogue
• Tab - Toggle dialogue skip
• Page Up - Roll back to earlier dialogue
• Page Down - Roll back to later dialogue
• H Key - Hide user interface 
• S Key - Take screenshot
• V Key - Toggle assistive self-voicing
• Shift + A Key - Open accessibility menu