The actual, legal, compressed size of The Witcher: Enhanced Edition (Director’s Cut) on GOG.com is about 4.5 GB . That is already highly optimized. If you see a file smaller than 2 GB, you are likely sacrificing the voice acting.
Pros:
"You look... simplified," a voice chirped. It was Dandelion, or at least a low-polygon approximation of him. His lute lacked strings, and his hat was a single purple triangle. "But don't worry, Geralt! The core is still there. The choices, the blood, the monster slaying—it’s all been compressed into the essentials." witcher 1 highly compressed
While "highly compressed" unofficial versions (repacks) claim to shrink the game to a few gigabytes for easier downloading, the standard installation has the following footprints: The actual, legal, compressed size of The Witcher: