If a download is corrupt, use the Verify Integrity of Game Files tool in Steam settings rather than re-downloading from unverified sources.
Decompressing these files can take hours and puts heavy stress on your CPU , often taking longer than just downloading the full official version on a modern connection.
Compressed installers from unofficial sources are frequently flagged as trojans or contain malware such as crypto-miners.
~8 GB installed for the original 2010 release. 2. Risks of "Highly Compressed" Downloads
Downloading a "highly compressed" version of involves significant trade-offs and potential security risks compared to the official versions. While official installation files are compressed to speed up downloads, third-party "highly compressed" files often achieve smaller sizes by removing essential game content or using risky installer software. 1. Official Game Specifications
For context, the official Mafia II (Classic) requires approximately of free disk space. The Definitive Edition (remastered) is significantly larger, requiring 50 GB due to higher-resolution textures.