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Game Information
Release Date
Last Update
Orig PC Gender
Adult Themes

Version: 0.05

Version: 0.04

The Guinea Pig
by thegp

DISCLAIMER: I do not own any of the imagens / gifs in the file nor do I wish to profit in any way with them. If anyone finds any of the images offensive or has any copyright issues, contact me and the image will be immediately removed.


So, this is my first game on Twine. 

The content is in it's conceptual phase so far, so expect some bugs and typos.

I intend to update it monthly, and release periodic bugfixes as needed.

The Guinea Pig is an erotic "open world" HTML game focused on the transformation of the male protagonist by the a group of women he met as he moved out: his new girlfriend and his therapist and a new online contact are just some of them.


Future plans:

- Develop Ashley's story

- Delevop Kate's story

- Develop Lilly's story

- Delevop more outdoor activities

- Develop more of the restaurant job


Hope you guys enjoy it. :)


You play as a shy nerd guy who just moved out of his overprotective mother's house.

As he arrives in the city, he rents the apartment from the beautiful Ashley, a psychology student. As the MC doesn't have a job to pay the rent, he agrees to pay the rent by attending to some test therapy sessions conducted by Ashley. As thing progresses, the MC gets to discover more about his true self, as well as the devious secrets behind Ashley's kindess.

So far, there are only four characters in the game4

MC - A young adult who just moved to the city

Ashley - A psychology student that rents one of her apartments to the MC

Kate - A beautiful goth girl that suddenly gets interested in the MC

MC's Mother - Overprotective and looking for her missing son


- Added sporting clothes at Sport Stop at the mall
- Added two new nightwears. One male (default) and one female.
- Added gym. You can go there to work out
- Added the option to work out in your bedroom
- Added hygiene stat. Now, you'll need a shower if you want to do stuff
- Added hygiene effects to previous events in the game
- Added limitations of how much guitar you can play on the park for one day
- Added limitations of how much TV you can watch for one day
- Added limitations of how much Video Games you can play for one day
- Added one more chapter of Lilly's story
- Added one more chapter to Ashley and Kate's story
- If you play too much guitar, your guitar strings may break and you might need to go buy new ones at the mall
- Watching porn now gets you aroused
- Previous interactions with Ashley and Kate will now affect your arousal level
- Going to work aroused will now have consequences
- Fixed body hair growth
- Fixed some typos
- Fixed some other minor bugs encontered during testing



- Added view modes for the avatar (now you can quickly view their underwear and naked body)

- Added more chapters to Kate history

- Added the fist chapter of Lilly's history

- The beach is now available (once you are feminine enough to wear female bathing suits)

- Added a guitar that can be bought at the shopping mall and played at the park for some extra bucks

- Added the first history chapters where the MC will really go fall deeper into feminization

- Added specific cutscenes for each piece of clothing that you change in the wardrobe

- Added sleeping attires for higher feminity MC (will still add some more in the future for high and low feminity)

- Added some more cutscenes for watching TV and playing video games.

- Added arousal stat. It's not completly functional yet, but it's there. More will come on the next update.

- Fixed lots of bugs concerning the new features

- Fixed some other minor bugs I've found while testing the game

- Fixed some typos



- Added more conditional images with for some activities while feminity stat is low

- Added more content to Ashley's story

- Added more content to Kate's story

- Added a new event at the restaurant job. A new girl called Lilly will appear and you'll will have some other person to talk to (just the introduction has been implemented so far)

- Minor changes to the journal interface. Nothing big, but it's there

- Optimized many of the games images, reducing the game size by almost 40%

- Fixed a lot of grammatical mistakes. I'm sure there's a lot more. I'm still looking for them

- Fixed story progression. making some previous events feel more natural

- Fixed some minor bugs I've found while testing the game



- Fixed socks not appearing at the wardrobe

- Fixed money maxing out after game start

- Fixed text for "Looking for a job" screen not appearing after you got the restaurant job

- Added messages for when history content ends

- Added a "Kill Time" option on the living room in order to instantly skip to nigh time

- Added conditional male images for some of the home interactions to appear when feminity is low



- Initial Release

- Fixed a lot of grammatical mistakes. I'm sure there's a lot. I'm still looking for them

Latest Reviews - View All Reviews

Review by nltog

Version reviewed: 0.05 on 06/18/2022

It'ss an early version so hard to criticise, but there's one thing that I simply cannot help but mention and it really ruins the experience. The interface and amount of times one has to click to do things. At the moment the game seems to be following the format of forcing user to go through the same dozen options each morning. Go to bathroom, shower, brush teath, washup, go to living room, go outside... Please, for the love of all that is holly, add an "auto bathroom" option so users don't have to grind pointless actions.

Review by cr0ssdre55er

Version reviewed: 0.05 on 06/16/2022

I love the game but wish there were a hint system for when the game gets a bit grindy espically after lilly sends the selfie revealing her true self

Review by zur

Version reviewed: 0.03 on 06/09/2022

Good game, very little content yet, but it has potential.

Review by JaradLichLord

Version reviewed: 0.03 on 06/07/2022

First, I believe this game has a great deal of potential, so much of the work into setting up the game has already happened with content needing to be added to this frame. However, I am not sure it really counts as a TF game yet for a couple of reasons: 

spoilers below 

1) the mental changes are that you enjoy wearing panties and undergo hypnosis. You really don't see any effects of the hypnosis yet(there is a scene that suggests that you had a major change but the paperdoll does not reflect it and their is no description of what actually happened. Does a change no one sees constitute a change?)

2) There are no physical changes to your character, I can see the set up for them is there, we have pink pills and the character will start wearing panties if you pursue the optional kate path but this really barely constitutes feminization.

I look forward to more content as I am certain this game is going to start expanding on those weaknesses detailed above.

Review by hallodaar123

Version reviewed: 0.03 on 06/07/2022

for a concept it is really good. there is so much potential. when you play the game and explore a little bit you can see the plans. like its almost natural to look for events happening. obviously events that arent there yet, but that I felt like looking for them, understanding what is to come, trying to wear different clothes to events, constantly checking my stats to see if I can find anything new with a higher level in something, that really says something about the quality of this game in my eyes.


I saw that there will be multiple possible jobs, you can walk in the park, explore the city. lots of possibilities for random events and/or storylines, which Im sure off will come. 

deffo worth it to follow this one. its a great concept if ur into forced femenisation and mind control ish things.

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