Virtua Tennis 2 Pc Highly Compressed Full 10 - Mb Only13 Exclusive Portable

In the world of lossless data compression (like ZIP or RAR), this is mathematically impossible for game assets. You cannot squeeze a high-fidelity 3D stadium and the distinct grunts of a tennis pro into a file size smaller than a low-resolution photograph. So, what exactly was this "10 MB exclusive"?