To download a highly compressed version of Serious Sam 3, you can try the following:

Most repacks include a Crack or CODEX folder. Copy its contents into your game’s root folder, overwriting files.

Launch the Game: Use the desktop shortcut to start your mission against Mental’s hordes. Essential Tips for a Smooth Experience

Would you like more information on purchasing the game or finding a safe download source?

: Always keep your security software active when downloading files from the web. Serious Sam 3: BFE on Steam