Many sites offering "highly compressed" versions of popular games are fronts for malware, spyware, or ransomware. Your PC's security is worth more than a few saved gigabytes.
Here is why that story usually ends in a "Game Over" and how you can find a better path: The Risks of "Highly Compressed" Downloads left-4-dead-2-download-pc-highly-compressed
To get a game that small, "repackers" often strip out essential files like high-quality textures, music, or even the cinematic cutscenes. Many sites offering "highly compressed" versions of popular