Be cautious of third-party websites offering "Build 05222021" as a standalone download. These are often:
If your current installation is buggy, use the "Verify integrity of game files" feature in Steam to repair your build to the most stable version. Download Helldivers Build 05222021 OnLine
Unofficial copies that lack official online multiplayer support, which is the core of the Helldivers experience. Download Helldivers Build 05222021 OnLine