This signifies that the source of the game is GOG.com, a digital storefront known for providing DRM-free (Digital Rights Management-free) games. This means the game does not require an active internet connection or a specific launcher to run.

This indicates the specific patch version of the game. Version 1.0.1 typically includes initial "Day 1" bug fixes and performance optimisations following the retail launch.

It is important to note that files distributed via .rar archives on third-party sites often carry risks.

This version includes a "Horde Mode," which significantly increases the number of enemies on screen, and an achievements system to encourage multiple playthroughs. Deciphering the File Name