Connect your PSP to your PC via USB or use a card reader.
If you have a modern smartphone, you don't even need a PSP. The PPSSPP emulator (available on Google Play and Windows Store) runs these compressed Batman games at 4x the original resolution. batman psp highly compressed
Here is the crucial part: A stock PSP will not play compressed CSO files. You need Custom Firmware (CFW) like PRO-C or ARK-4. CFW unlocks the PSP’s ability to read compressed ISOs from the memory stick rather than the UMD drive. (Note: Installing CFW requires checking your PSP model and current firmware version. It is a software modification, not a physical one). Connect your PSP to your PC via USB or use a card reader
Once you have your compressed file (ending in .CSO or .ISO), here is how to install it on a real PSP (Custom Firmware required). Note for PS Vita users (Adrenaline): Highly compressed
Note for PS Vita users (Adrenaline): Highly compressed CSOs work perfectly inside Adrenaline (the PSP emulator for Vita).
The easiest way to play these games today is on your smartphone or PC using the PPSSPP Emulator.
Disconnect USB. Go to Game > Memory Stick. Your Batman game should appear. Tap "X" to save the streets of Gotham.