For the official version (or a clean ISO), the installation process is straightforward:
The tighter the compression, the higher the chance that a single missing or corrupted byte will ruin the entire archive. You run a major risk of downloading a 5GB file only to receive an "archive corrupted" error during installation. Security and Malware Risks Mortal Kombat X Iso Highly Compressed
Wait, compressing an ISO itself isn't illegal. It's the distribution and use of pirated content that's the issue. So if someone has a legitimate copy, compressing the ISO for personal use is okay. However, the line is when you take a game you didn't purchase and compress its ISO for others. Need to clarify that. For the official version (or a clean ISO),