I will not be updating this repository any more, as the project has moved to C++ at https://github.com/RealTheSunCat/Minecraft4k-CPP to enable GPU acceleration. This is the last version of the Java build.
This is the smallest I was able to get the executable with all of the added features. I used ProGuard to strip it of most data, which reduced the initial 33kb build to nearly half its size. Let me know if you manage to shrink it further!
I have attached a jar file with updated world generationm ray-marched shadows, and a custom texture pack (Minecraft4k-custom.jar), and a jar file that attempts to keep as much of the original version as possible (Minecraft4k.jar). You can change which version is built in the source code by changing the classic boolean.