Refine project documentation and .gitignore: update links, remove unnecessary build files, and adjust code block formatting

.gitignore

@@ -10,6 +10,5 @@
 Thumbs.db
 
 # Build files
-build/
 bin/
 obj/

README.md

@@ -38,9 +38,11 @@ It's therapy through comedy. It's dark. It's sincere. It's ridiculous. It's all
 
 **Early Access / In Development** – We're building this lean and mean with a 2-person team + AI tools. Expect rapid iteration, unfiltered creative decisions, and occasional chaos.
 
+Implementation status is planned in [DEVELOPMENT_ROADMAP.md](docs/DEVELOPMENT_ROADMAP.md) and changes are tracked in the [changelog](CHANGELOG.md).
+
 ## Credits
 
-Made by two people who thought this was funny enough to be real.
+Made by two people who thought this was funny enough to be real. [Corey](https://coreypellizzi.com) had to undergo cancer treatment himself, which inspired this project. [Georg](https://github.com/Zwitschi) takes care of the technical aspects and makes sure the game actually runs.
 
 ## License
 
@@ -59,6 +61,6 @@ Steam Early Access coming Q3 2026. Wishlist to keep up.
 
 Follow the chaos: [Discord] [Twitter] [TikTok]
 
-[Discord]: https://discord.gg/yougetchemo
+[Discord]: https://discord.gg/chemo-sim
-[Twitter]: https://twitter.com/yougetchemo
+[Twitter]: https://twitter.com/chemo-sim
-[TikTok]: https://www.tiktok.com/@yougetchemo
+[TikTok]: https://www.tiktok.com/@chemo-sim

docs/GAME_DESIGN_DOCUMENT.md

@@ -21,7 +21,7 @@ First-person chemo simulator. Painfully accurate. Darkly funny. You don't beat c
 
 ## Gameplay Loop
 
-```
+```txt
 Arrive at hospital → Check in → Wait (minigames happen here) → Treatment session → Side effects kick in → Go home → Cope → Repeat
 ```