Do you want to play Build 14344626 without risking a virus or a cease-and-desist? If you legally own ULTRAKILL on Steam, there is a legitimate method:
This method is legal because you are using your own license to download Steam’s historical files. The catch? It requires 30+ GB of free space and knowledge of command-line tools. Most users skip this and grab the .zip file instead—which brings us full circle. ULTRAKILL.Build 14344626.zip
The "story" of the build is also defined by the tools the player was given. This update introduced: If it's a mod or community build: