Project Mental is a 3D adult sandbox simulator built with Unreal Engine by MentalCopy. It combines real-time play with RPG elements, offering a mod-friendly open-ended style inspired by Skyrim, Sims, and Fallout. In the current build, you can control a male character while the story of ONI begins, and three new characters appear. The game supports English on Windows and is intended for adult players.
The latest version is v1.2.8b, released on March 9, 2025, and development is ongoing. It is uncensored. This update adds a playable male character, the start of ONI's storytelling, three new characters, many new animations, and real-time semen physics. Earlier content includes the Massage Salon location and a revamped secretary model, along with main menu and interaction changes.
Developer's description
Project Mental, an immersive real-time adult RPG adventure!
Spoiler
Greetings, my dear perverts!
Project Mental is a 3D hentai sex simulator & sandbox with RPG elements.
This is a sim based game, which means the idea to
let you do what ever you want in a real-time sandbox, "Freedom for fantasies without borders".
My idea or better to say goal to build a perfect and mod supported adult sandbox game,
with elements of Skyrim, Sims, Fallout etc.
v1.2.8b
- Playable male character.
- ONI's storytelling begins.
- Three new characters
- Tons of new animations.
- Real-time semen physics in every iteration.
- And so much more.
v0.11b
The first quest has been added! You can find it in the “Massage Salon” location.
The Massage Salon has received a small map design update, and the secretary character model has been completely revamped.
The main menu scene and interaction UI has been altered and improved.
This update is significant since it provides new possibilities thanks to which numerous quests will be build within several clicks.
In prospect, our updates will be of two varieties:
1. Reworking old content: We’ll be remaking old dialogues and systems and replacing it with new one which you already can see in Massage saloon.
2. New Quests + Sex events: Next quest will take a place at Home between Emiko and Oni that’s will be pure storytelling quest but ofc with elements of lust and fun.
v0.0.9
1. Rei model remake (with a huge list of innovations)
2. Rei new dialogue options
3. Rei non-sex animations (5)
4. Rei voice lines (13)
5. Rei sex event system
6. Rei sex event options (5)
7. Rei sex animations (47)
8. A huge code optimization
v0.0.8
- Unique event with Ugly Bast*rd
- Characters shader improvement
- Semen, Saliva, slime visual effects
v0.0.7
- New type of event which can be found at House/Attic. [Experimental]
- Mini petting cat event. [Massage salon]
- Lots of UI improvements and additions.
v0.0.6
Game
Brand-new map to explore.
A complete makeover for our old maps.
New characters.
Extensive optimization.
Graphic enhancements.
Old animations improvements.
A huge number of new animations added.
And much more.
Team
I am happy to introduce 3 new members of our team!
Kure, our level artist
OlegPBP, a seasoned C++ programmer
Taro, our expert in Japanese and Chinese localization
v0.0.5 Is finally here ! This update brings new locations new scenes, new events and much, much more.
A lot of old content was improved and updated or in some cases was even completely re-done from scratch, so I hope you will be happy to play it!
Added/Updated
-Added new character Deads (Brainless followers of the underworld King)
-Added new character Priest (Guards of the underworld King)
-Added new character's Poor Girls (The name speaks for itself, basically it's slave girls which can be found at location Cave)
-Added new character, Underworld King (Unknown monster)
-Added new character, Faceless man (For location Clinic)
-Added a small NPC like (Tentacles, Monster cocks etc.)
-Added new location (Cave)
-Full re-work of location (Clinic)
-Update of location (Home)
-Added world map
-Added Travel-system
-Added 15 sex events (up to 29 sex animations)
-Xmas props
-New type of sex mini-games
-Quest manager
-New hair-styles
-Added 90 sex-toys
-New engine for animation
-16 cutscenes
-Updated 47 UI elements
-Improved UI elements 9
-And much, much more!
v0.0.3
Fixes & Additions
Fixed an issue where the player was duplicated in sex-scenes
Fixed an issue with lights and shadows
Fixed issue with incorrect reflections on characters
Fixed a bug where the game required much more RAM than needed
Fixed 19 interface bugs that caused lag
Fixed a ton of small bugs with characters
Texture size fix to improve performance and avoid blurry effect
Alternative shipping method of the game was fixed to avoid Input bugs
Added 2 lesbian scenes [Rei]
Added 2 scenes with cross [Emiko x Oni]
Added 2 sofa scenes [Emiko solo]
Added 2 oni bed scenes [Emiko x Oni]
Added 4 Non-sex scenes
Added new Interaction furniture 5
Re-work of location [Home]
All rooms at location home now available
Added day mode [Currently on] (In story mode will be based on game time)
29 Elements of UI were re-designed
Phone system added [placeholder atm]
v0.0.2
Fixes:
Improved performance
Completely re-made hairs & new hair physics
Cursor disappear if you hit ESC in sex scenes
Adding twice the same animation to the scene
Materials of the Emiko was optimized and re-done
All interface elements were updated & fixed few issues with it
Tone of small bugs
New additions
New character Rei was added
Character Oni was re-made
Added 2 shower scenes
Added 9 sex animations
New hairs & hairs physics
BDSM room
New toys to play with 2
New shader (performance boost)
Small locations update
Demo
Initial Release
Player reviews
Player rating3.5 / 5 · 10 ratings
Written reviews10 · avg 3.3★
Positive (4–5★)50%
Latest review2023-12-16
What players say
Reviews are mixed, praising visuals and animations but noting limited content and technical issues.
5★2
4★3
3★2
2★2
1★1
Players like
Good graphics and appealing character models
Plenty of sex animations
Promising foundation and future potential
Interesting environments and a large house
Common complaints
Limited content and short demo
Bugs, clipping, and technical issues
Minimal gameplay and missing story
Best for players who enjoy early demos and sex animation showcases.
Summarised from 10 written player reviews.
chwant2023-12-16★★★★★
I really don't get what people are liking in this quite badly done tech (?) demo. Anyone who has a day or two experience in UE would see that the developers did not event touch the some of the default…
powhattan2023-11-23★★★★★
The astro turphing of a test demo is unbelievable. The free version is at best a concept test demo, showcasing sex animations with "customisation" being what clothes you can wear that are immediately undone as soon as you interact with…
Gixxer2023-11-19★★★★★
I have never typed a review here but this game is actually amazing with huge potential. Considering it is still in early stage but the graphics, gameplay, animations, and the MC are all great! I haven't played since the 0.0.3…