cyberpunkdreams is a massive (over 2.8 million word) cyberpunk interaction fiction/RPG. It's free to play on Steam. It's written on a custom engine and also featues over 3,000 unique hand-drawn images, and all of this is currently growing. The game is in full release and has been for a few years, but gets regular updates.

Although it's not primarily an adult game, it contains a lot of adult content. Romanaceable NPCs, one-off encounters, interactive sex scenes, third party sex scenes via "spikes" that you plug into your brain and more. And, of course, there are transformation themes. Mostly these are under the player's control and take the form of surgery and cybernetics, but there's an element of mind control and horror in some areas too (those "spikes" can also be used for other things...) Players can also start with sexual mutations, such as extra breasts and testicles or a literal horse penis. There are also a lot of wardrobe options.

All in all, there are a lot of combinations, and more planned (the items ticked on the list are only what's in the game now). Overall, it takes a semi-realistic approach to transformation -- surgery and pharmaceuticals, not magic wands.

There is also a dedicated Discord server and Patreon, but neither of these are required to play:

Patreon: https://www.patreon.com/c/cyberpunkdreams2092 (includes a free tier)
Discord: https://discord.gg/cyberpunkdreams

The city is spread before you, horizon to horizon, a vast sore squatting on the world. 24 million people, most of it lawless slum and favela. The last outpost of civilisation on the edge of the badlands. One of the most relevant, cosmopolitan cities in the world. Is it any wonder you ended up here?

cyberpunkdreams is an evolving text-based role-playing adventure with countless opportunities and endless chances for creation and destruction. Take on the role of a lone wanderer sent to the gates of 2090s Cincinnati. The dirt and grit from the badlands coats your clothes -- with your memories torn from you, all you have is a weapon across your back and a mission to complete.

Enter a living, growing world, with over 2.8 million words of content and over 3,000 unique pieces of hand-drawn artwork, Experience new stories and other content each and every month, plus regular limited time events. You’ll always find new surprises waiting for you in Cinci's dark and dirty alleys.

Who will you become in this cesspool of a city? Will you play the games and climb to the top, or be forgotten amongst the march of time and tyranny?