Sex Formula is a 3D animated adult relationship game from MIGI STUDIO, built in Unity. You play as a male protagonist who meets Reika and starts a life with her. The narrative focuses on building a romantic connection. Reika will not agree to date the player unless he satisfies her sexually, even when a physical connection already exists.
The current build is v2.1.0, released on September 22, 2026, and development is ongoing. It runs on Windows 7 and Windows 10, supports English, Japanese, and Chinese, and is uncensored. The latest changelog adds cloud saving, new appearance and nail customization options, VR character movement choices such as teleportation and horizontal movement, and twelve animations. These additions expand customization and movement options.
Developer's description
This game narrates how the player meets Reika and begins a life together. Before satisfying Reika sexually, she will not agree to date you, even if you already have a physical relationship.
v2.1.0
[Features]
● Added - Cloud Save
[Custom Appearance]
● Added - 1 nipple style
● Added - 1 nail style
[VR Features]
● Added - Character Movement Options
*[Teleportation] - Aim the right-hand controller at the floor and move the joystick to teleport to the selected location
*[Horizontal Movement] - Move the joystick on the right-hand controller to move the character (Players who are prone to 3D motion sickness should use this with caution.)
[Animations]
● Added - 12 animations (Bathroom, missionary position)
v2.0.0
[Features]
● Added - Repeat Dance Button
● Added - Automatic Hicky Display
● Added - Automatic Semen Effect Display
● Added - Automatic Cleanup After Oral Sex Settings
1. Always
2. Random
3. Never
● Added - Separate Semen Effects for Face and Mouth
(For example, semen can be inside the mouth while also visible on the face.)
● Fixed - Floating fluid appearing in front of the male protagonist's penis during story scenes
[Outfits]
● Added groin-pulled-aside variants for certain outfits
● Fixed - Glasses were not saved correctly when saving outfit presets
[VR Features]
● Fixed - Floor movement destination indicator display
[Animations]
● Added - 8 New Animations (Kitchen Standing Position)
v1.9.0
● Fixed an issue where the achievement for the memory (recollection) feature could not be unlocked.
●New animation x 10 (Kitchen DoggyStyle)
v1.8.0
[Animation]
●New animation x 6 (Kitchen OnTop)
●New main screen animation x 1
[Function]
●New facial appearances x 2
v1.7.0
●New animation x 12 (Kitchen Missionary)
●New clothing x 1
v1.6.0
●Added liquid effect display switch
●New animation x 8 (Bedroom Standing Position)
v1.5.0
●New animation x 10 (Bedroom DoggyStyle Position)
●New opening animation x 1
●New Hairstyle x 1
v1.4
Hello everyone, Sex Formula v1.4.0 has been updated
The revised contents are as follows
[interface]
●Tab Key will no longer hide subtitles
[Animation]
●New animation x 6 (Bedroom Ontop Position)
[clothing]
●New clothing x 1
[Function]
●New Hair Material (B)
●Added color settings for hair material (B)
●When you leave the game, the current clothing settings will be recorded
v1.3
[interface]
●Remove [Auto Position] function
●Add [Frame Rate] settings function
[animation]
●New animation x 12 (Missionary in Bedroom)
[clothing]
●New clothing x 1
[Function]
●Repair clothing judgment
●Fixed the DirtyTalk voice volume function
●Fix the voice volume function
●Fixed the problem of being unable to talk after pregnancy
●Fixed the problem that the recall function cannot trigger achievements
v1.2
[interface]
●Newly added foreplay and sex button number markers
●Display correction in some languages
[animation]
●New start screen x 2
●Some animation corrections
[clothing]
●Newly added high heels x 1
●New clothing x 1
[Function]
●Newly added camera close to Reika’s lips for kissing
●Newly added camera is close to Reika’s breasts and can be sucked and touched
Note 1: Reika must show her breasts
Note 2: [If the left and right breasts are touched at the same time, the first touch is: sucking, the last touch is: touching]
●Newly added mobile camera can be changed to right click
●Added hotkey [F] to switch cameras
●Newly added hotkeys [1,2,3,4] to switch camera focus
[VR function]
●VR has added the ability to kiss Reika by putting the helmet close to her lips
●VR newly added: Put the helmet close to Reika’s chest and you can suck and caress it
Note 1: Reika must show her breasts
Note 2: [If the left and right breasts are touched at the same time, the first touch is: sucking, the last touch is: touching]
v1.1.2
[BUG]
●Mouse sensitivity default correction
●After the settlement animation, you cannot have sex normally.
v1.1.1
[interface]
●Added game settings [Screen][Control] tab.
●Added mouse sensitivity setting.
●Resolution-related changes to the drop-down menu.
[Function]
●Added [Next Week] button.
[BUG]
●Some animation and lighting corrections.
●Corrected the transparency judgment of stockings.
●Correction of dialogue window judgment has been corrected.
●Correction of achievement triggering function.
●Correct the initial position of each room.
●Delete the black cutscene before the scoring animation.
[VR BUG]
●VR Corrected the [Dirty talk] playback frequency function of the game settings.
●VR If sex ends with sexual intercourse, switching POV will cause the Xray window to go out
●After two consecutive sex sessions in VR, the cutscene effect did not appear.
v1.1.0
[interface]
●Some translation corrections
●Condom button switch identification
[Function]
●Added automatic cleaning settings
●4K resolution is changed to Ultra, and to 2K (2560x1440), 4K (3840x2160), 8K (7680x4320) resolution
[BUG]
●Stockings will disappear under water
●After triggering the promotion relationship, the window perspective function becomes invalid.
●Automatically put on condoms without closing the see-through window
●Correction of some FPS lens angles
[VR-interface]
●VR-Game settings add POV camera effect switch (replaces the original correction lens function)
[VR-Function]
●VR-A and X keys are grab buttons
●VR-Y key can call game settings
●VR-B key can quickly switch [first person] [default]
●VR-During sex, press the left selection button to drag the lens
[VR-BUG]
●VR-A perspective window will appear during settlement
v1.0.1
[clothing]
●The upper body of the policewoman costume will disappear when settling the account
[interface]
●Some text translation issues
●New [System] page for game settings
●[Game Settings] - [System] Added [Return to Home Page], [Exit Game]
[Function]
●Change the time spent to spend the day
●Added higher resolution 4K 3840 x 2160
●New automatic orgasm and ejaculation options in game settings
[BUG]
●After Reika gives birth, approaching Reika cannot trigger dialogue.
●Memories can also trigger achievements
●When clicking on ejaculation or orgasm in a non-penetration state, it does not detect whether the see-through window is open.
v1.0.0
Initial Release
Player reviews
Player rating3.5 / 5 · 20 ratings
Written reviews20 · avg 3.4★
Positive (4–5★)50%
Latest review2026-03-09
What players say
Reviews are mixed: many praise the sex animations, while others criticize the short, shallow gameplay and technical issues.
5★7
4★3
3★4
2★3
1★3
Players like
Engaging, well-made sex animations
Attractive main character model
Detailed x-ray visuals
Pregnancy and cycle features
Common complaints
Very short, repetitive content
Weak story and minimal gameplay
Technical bugs and performance issues
Best for players who prioritize erotic animations over story and gameplay
Summarised from 20 written player reviews.
verodor2026-03-09★★★★★
The positive is that this game has some quite sophisticated animations and they are indeed engaging. The story itself is nothing to write home for and the short gamplay-loop makes it that after about 2 hours you have already seen…
beefenstein2025-12-30★★★★★
2 stars for the sex animations. Everything else about this game is just bad, from the terrible dialogue and story to the cringy voice acting and plasticky graphics that somehow manage to go above and beyond to look extra artificial…
werkausburg2025-12-27★★★★★
It is an empty game, the character customization is poor and extremely empty, the same with the poses, there is nothing to do in the game, it seems like a poorly finished beta, I don't know why they released this…