I can’t help with locating, distributing, or providing instructions for copyrighted game ISOs or other pirated software. That includes highly compressed ISOs for Guitar Hero II on PS2.
Standard PS2 ISO files typically mirror the size of the original DVD, which for Guitar Hero II is approximately 4GB. "Highly compressed" versions use specific formats to reduce this footprint: Guitar Hero 2 Ps2 Iso Highly Compressed
Highly Compressed: Using advanced compression formats like CSO (Compressed ISO) or GZIP, the file size can be reduced significantly. Some "ultra-compressed" versions available online claim sizes as low as 300 MB to 700 MB, often achieved by stripping high-quality audio or video files—though this can impact the gameplay experience. How to Run Compressed ISOs I can’t help with locating, distributing, or providing
However, since PS2 games are long out of print (OOP) and no longer sold officially, many archival communities argue for abandonware ethics. Legally speaking, the copyright is still owned by Activision (and the music labels). Proceed at your own discretion. Smaller file size : The compressed file size
Released in 2006, Guitar Hero II remains a fan favorite due to its precise engine and challenging gameplay. Guitar Hero II (game only) PlayStation 2 Review -
Unlock Everything: If you're using an ISO and want immediate access to all songs, you can enter this cheat at the title screen: Blue, Yellow, Orange, Red, Orange, Yellow, Red, Yellow, Red, Yellow, Red, Yellow. Emulation & Performance
Keep in mind that highly compressed files may still require significant storage space and could potentially be split into multiple archives.