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Adult Themes

Version: 0.42


Explore a fantasy world that seems intent on transforming the player into something else…

Yaffaif is an adult text-adventure or text-based role playing game in a “fantasy” setting (however, it has a graphical interface that tries to eliminate the main frustrations of textual input. So no endless typing input (unless that’s your thing - in which case enjoy the auto-complete of words).


The main theme is slow transformation, of which weight gain is a part. One of the reasons for buiding a bespoke engine is to provide the necessary detailed character descriptions. The main plot is advanced by compleing various quests and in general there will be a couple of ways to do this: one accepting transformations of the player character, and a (usually) more difficult or grindy way where you don’t. A key design choice is that transformations have consequences - they aren’t just modifications of the character’s description. It is also open-world too; there’s no necessity to complete the various quests. If you want to settle down, romance a partner, end eventually raise a family you could do that too.

Also included:

  • anthropomorphic (furry/monster) NPCs and transformations
  • voluntary (or at least avoidable) transformation (weight, species, size, gender)
  • clothing bursting, furniture breaking, getting stuck, and immobility
  • turn-based combat (in the style of OSRIC/old school DnD)
  • turn-based sex (m/f, m/m, f/f, and more)

Character generator allows you to start as male or female with a choice of species, height, weight, and so on.

Planned transformations also include: M2F, F2M, Bodyswap, Possession, Pregnancy, Inflation, Grow, and Anthros.

Can I ask that if you find a bug that you report it on the forum (use the discussion/help link to the left, or the dedicated board on Weight Gaming https://forum.weightgaming.com/c/curated-projects/yaffaif ) rather than mention it in any review. It will make it more likely that I'll see it (as reviews aren't notified to creators), and allows me to reply if I need more information, or if I can explain why it is currently happening. Thank you.

In the village:

  • You: the protagonist
  • Alexis Ward: a guard
  • Arthur Butterworth: the barman in The Roses
  • Dot Drostock: a seamstress (coming soonish)
  • Geoff Smith: the village smith
  • Kerry Sidbothom: a healer and nurse
  • Orion Griffiths: the stranger in The Roses

In the Mine:

  • Alfred Garnett: the night guard
  • Arawan Crowther: the business partner
  • Dezinah Hronfelt: the queen
  • Frank Coke: the put-upon cook and barkeep
  • Gart Rogan: a guard
  • Karl Hronfelt: a guard and a prince
  • Rochaine Kalach: a “tour guide” and airhead

Twizelford Road

  • Dave “gimmie” Cobble: a bandit
  • Elise “rabbit” Cobble: a bandit
  • Jim “big” Cobble: a bandit
  • Kelsi “click” Gale: a thief
  • Nug: an orc


  • Buttercup: a cow girl and shopkeeper
  • Bluebelle: a cow girl and farm worker


  • Ruffus Steele: a member of the civilian guard
  • Darthen Summat: a civilian guard
  • Lola Lovell: owner of Beers



The built-in quest tracking system is intended to provide enough of a guide for the majority of players. In general each quest can be solved in multiple ways. However a detailed walkthough (including maps and cheats) is available as a Patreon benefit.

0.43: [Patreon EA]: Dathren alley encounter (and parent's quest progression)

0.42: 2021-05-10: Beers open, meet Dathen, pre-flight Java checks

0.41: 2021-04-10: Revenge parents quest (unfinished), get dry quest, civilian guard building, scalable UI

0.40: Bugged

0.39: 2021-03-10: Shops laundry/alterations/repairs and buying old items

0.38: 2021-02-10: Hillside and town areas, door locks

0.37: 2021-01-10: Height and skin colour transformations, bughunt

0.36: 2020-11-21: Farmhouse, obeying orders

0.35: 2020-10-24: Cow/bull transformation, breastfeeding

0.34: 2020-09-19: Farm shop

0.33: 2020-08-19: Lockpick skill, Twizelford road capture

0.32: 2020-07-10: Gods, shrines, fetishes, bandit quest, road to Twizelford

0.31: 2020-06-08: Fatigue, sleep & dreams, start main quest

0.30: 2020-05-03: Village shop, smith job.

0.29: 2020-04-08: Gate guard, skunks, body fat changes, supporters, Patreon changes

0.28: 2020-02-20: Bughunt.

0.27: 2020-02-17: Giving the UI some love. Bugs fixed.

0.26: 2019-11-27: Orion's quest can be completed (or failed). Many bugs fixed.

0.25: 2019-11-10: Windows batch files, quest fixes, patrolling guard.

0.24 2019-06-02: Sleeping, eye-colour, family name, bug fixes

0.23: 2017-12-10: Bug Fixes

0.22: 2017-12-05: NPC lust defeat. Athrowable lust potion. Kissing, breast fondling, cock-sucking, sleeping. Major internal changes.

0.21: 2016-04-23: Coloured text. Fixes.

0.20: 2015-04-04: Breakable furniture. More internal work.

0.19: 2015-09-08: Keys and locks. First real version of masturbation. Female sex toys. Many internal changes.

0.18: 2015-03-05: Character generator. Text commands can include prepositions so "ask about", "ask for", "tell about" "put on" etc. work. New web hosting.

0.17: 2015-01-04: Auto-complete. Java 8 only.

0.16: 2015-01-01: Not released due to bug.

0.15: 2014-11-21: Java 8 compatibility. More body modelling. Quit from command line.

0.14: 2014-09-03: Big internal rework - so hopefully no more odd combat. Bug fixes. Male genitalia. More iron to find. Clothing can be destroyed. In place of a character generator, there are F->M and fox->human potions in your house bedroom if you don't want to be a female fox. Website changed to offer more help to install, play, and debug.

0.13: 2014-08-08 Eels alive version. Along with many bug fixes, there's a new creature in the pit. Unfortunately this has exposed a bug that requires a deep fix, so this is a bit of a checkpoint version.

0.12: 2014-04-23 Phantom flan flinger version. There's a new weapon in the mine, and you don't have it, but you can make them. NOTE: It is now possible to be defeated in combat by arousal, but nothing then happens!

0.11: 2014-01-01 The first version with transformation content (in the mine area). Also fixed a major bug in the combat system which could result in weird zombie NPCs.

0.10: 2013-10-16 The first version of the text parser is live. You can now enter commands in the bottom left text box instead of using the various buttons. Be aware that handling of miss-understood input is a bit ropey, and may spit out debug messages sometimes. The "talk" command doesn't work yet, so you can't play without using the buttons in places. Also there's no Infocom sytle 'I' or 'L' yet. Many bugs fixed (like humans having tails).

0.09: 2013-06-06 Adds hair and gets rid of a particularly nasty bug between the core library and the UI that messed up combat and a few other things. Colours are now modelled in a way that allows them to be transformed.

0.08: 2013-05-03 Adds tails, describing some naked body parts, examining clothing, a trapdoor, and a little more mine content. There's a sanity check on startup that exposed many now-fixed bugs (hence the delay).

0.07: 2013-02-12 Fixes significant bug when loading saved games that caused missing text and actions. There's a little bit more to explore in the mine workings. Internal work includes factions and trapdoors.

0.06: 2012-12-07 Major re-write of character description code which can now describe more stuff including the fit of clothes. Quests added (you can only complete the first weapon one with this version). Armour added. Possibility of getting rescued if you die in some areas. Clothing no longer goes to inventory tab when removed. Many bug fixes.

0.05: Added some potions to play with in the still hut (these are temporary additions). Assorted Bug fixes.

Latest Reviews - View All Reviews

Review by foxdsx

Version reviewed: 0.36 on 11/23/2020

its a kind of game that even if its ok i will never play again( outdated contol )

Review by Kei-chan

Version reviewed: 0.22 on 12/07/2017

Nice necropost in response to a review over a year old, guy. Nobody cares if you like muscle growth or weight gain, or why, and nobody wants to argue it with you. Nobody goes around screaming about how every game posted here is bimbofication, sissification, or has no TF elements whatsoever, so I'm sort of with this dude in that it's fucking bizarre the lengths that people will go to when a game with weight gain is posted here.

Anyhow, in regards to Yaffaif, it hasn't had new content added in years. As long as I've been aware of its existence, you talk to the guy in the bar, go to the mines, get a tour from that kobold, then when you enter the throne room they all inexplicably turn hostile and there's nothing else to do in the game. Not sure what the latest update was, but it seems that the custard in the mines no longer transforms you into a kobold, so there's actually less to do now than there ever has been before.

Also worth mentioning that flirting or kissing an NPC with a function (such as Arthur) will permanently remove any other dialogue options with them, and that the testing items northwest of your house bug out after moving around a bit, causing your weight to revert or your description to break. Weird shit, never saw it before. Hard to tell what might be causing it without knowing what changed between 0.21 and this.

Review by Jhal3mbustion

Version reviewed: 0.21 on 05/16/2016

This is a review by and for someone who actually likes weight gain and does not really understand why it is so unpopular with these gamers who are so open to transformation. (I think that probably has to do with so much propaganda and trust in false health studies. Weight changes, muscle growth and gender transformations should be considered the most vanilla transformation fetishes, but discrimination somehow manages to exist even within these communities.)

Anyway, this game in its current state seems like it will always be very dividing for the vast majority of people. And the reason for that should be cannibal and furry elements. While cannibalism and becoming an animal go hand-in-hand, it definitely makes me uncomfortable playing this game. But it gets worse since this demo allows humans to eat other humans. This is just deeply disturbing and this content should be possible to turn off for players who do not want it. 

But why would I complain about cannibalism? I accidentally killed both the Kobolds and the bar owner (Arthur) and found out that I would simply be forced to eat him if i wanted to get anymore food without transforming into an animal. This game in its current state has a disgusting over-obsession with meat, raw meat in particular, which makes me feel like a human character is not even supposed to exist in it. Why does the bar have to give me beef pies as the main food? It is such a disgusting food. There should be a bakery and restaurant in the game because gaining is not really fun with an all-meat diet. In fact, I don't believe that it is actually possible to get fat on solely meat (at least, it is probably very unsafe and expensive). Promoting a human eating raw meat which will give them deadly parasites is not a good thing.

This game forces too many potentially disturbing fetishes on people. I hate the idea of facing infinitely looping traps that transform the player or eating food that transforms the player. I am pretty sure that I missed a major plot point, but I found it annoying that the anthromorphic animals were eating only food that turned them into what they already are. They probably were evil in the first place, but I ended up offending them and killing them and seemingly ending the game. The way the transformation is described in shrinking your height is both a great description and a very scary one, which makes me even less comfortable playing the game. If you do not make it possible to turn off, then the transformations should be only contained in questionable items or be presented in events that are obviously going to have an effect on the player instead of just walking in some direction and triggering a trap. Things like that should actually result in a game over. The game's lack of game over scenarios really does ruin the possibilities for flexibility since every good transformation game uses game overs effectively and some of the areas in the mine really sound like death hazards.

Another big problem is the lack of a feeling of belonging to the world. Yes, this is a game in a "proof-of-concept" state, but I just can not really get a feel for it if I do not understand the first thing about why there are some abnormalities with the house that are apparently from a fire, but do not seem like the familiar signs of fire damage. You can have a mystery, but there are a lot of details that the introduction should have been able to explain. The main character exists as if they were born yesterday, but the circumstances make it seem like something really bad happened that should have given them a reason to go on an adventure besides not being supported by parents anymore.

One last thing that annoyed me was the passage of time. It was kind of fun to be able to gain weight so rapidly with the unmeasured passage of time, but it also made me feel like there was no stopping point in the game, which is yet another thing that made me uncomfortable playing. When you examine the bed, it says that you sleep there every night, but the character stays awake forever somehow, like some kind of immortal. Time management seems like a huge necessity to make this game feel solid, even at a proof-of-concept level. 

My absolute lack of a comfortable understanding of what the game's focus on made it very hard to appreciate this demo, but I know that I am probably looking at it the wrong way.

But, I really do enjoy the things that I did not feel uncomfortable with. The different sized clothing is really cool (but there currently exists no real way to tell them apart except for trying them on). The idea of having fat NPCs (finally!) who are also more centered around consensual sex rather than rape was also refreshing. That said, it is annoying that every single character (even your own character, given the size trait of "average" weight) seems to be described as fat. It feels like reverse discrimination so, it is basically one step forward and one step back.

The fights were fun to play through and death is forgiving, which I liked (but it further makes the cannibalism of the game feel that much worse). Sex levels and regular levels with RPG experience points was really neat, but I hate how slowly they gained for a proof-of-concept because regular leveling was literally impossible and leveling for sex still took too long (especially without being able to sleep). You should have at least a few sample level-ups to show us what kind of stat increases happen.

My highest praise will go to the extremely well-detailed weight gain system. This system, unlike every other transformation game out there, uses real metrics, and I find that to be the best way to depict the state of a character. Being able to choose a pear shape body was a huge plus, too. The fact that I could select from about nine different pages to effectively explore the world really felt worthwhile and accessible and items/commands/etc. are arranged in a way that does not strain the eyes at all. I would say that this game captures much of the comfortable presentation that I enjoyed from Corruption of Champions because of the user interface, effective writing and hard work choices for raising stats.

Review by RedGhost

Version reviewed: 0.21 on 04/25/2016


An interesting game in development, as noted by other reviews the primary TF is weight-gain and everything connected to it. There is a furry element to it as well, but that more so sets than scene than anything else (think Corruption of Champions in the early days).

Overall in the time I spent playing the game the writing was interesting and descriptive, with the NPCs encountered mostly being basic (which is understandable given the early development of this game). But I wasn't interested in the TF the game is based around and found myself a bit bored as time went on.

This is a game that deserves a look at least with an open mind. Further developments would certainly be interesting, but I don't think the primary TF will change.

Review by Anon21

Version reviewed: 0.15 on 11/22/2014

This is a decent 'proof of concept' and I think it has a lot of potential as a game framework.

Now, as far as the actual game goes there are a few areas that I think could do with tweaking. First, I gather that the author has interest in weight gain situations. Nothing wrong with that. However I think that it is a too fast and forced at the moment. Practically the instant you start the game your character becomes 'famished' and, upon eating or drinking anything, she is on the verge of bursting out of her panties. After eating your character barely has enough time to explore her house before feeling hungry again.

In my opinion it would be more realistic, and more attractive to most players, if diet habits over a few days were responsible for dramatic messages like that. For those interested in that transformation path I would suggest having sweet or fattening foods available and giving ambiguous warning messages (e.g. "The strawberry tart is absolutely delicious, you'd like to eat another right now but you think you really shouldn't").

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