Because the PSP’s web browser could play .SWF files, clever trolls extracted the flash game Resident Evil: Zombie Bounce or the RE4: Las Plagas mini-game (a chibi shootout). You’d launch the "game" and get a 2D, unplayable demo that crashed on level two.
Resident Evil 4 " was never officially released for the PlayStation Portable (PSP)
Resident Evil On PSP: Can You Play It? - Formacionpoliticaisc
For nearly two decades, Resident Evil 4 has stood as a titan in the survival-horror genre. Originally released for the Nintendo GameCube in 2005, Capcom’s masterpiece has been ported, remastered, and re-released on nearly every platform imaginable: PS2, PS3, PS4, Xbox 360, Xbox One, PC, Wii, Switch, and even mobile devices (iOS/Android). However, there is one glaring omission from that list:
For nearly two decades, Resident Evil 4 has remained a gold standard in the survival horror and third-person shooter genres. Originally released on the GameCube in 2005, Capcom’s masterpiece has been ported to almost every platform imaginable: PlayStation 2, PC, Wii, Xbox 360, PlayStation 3, PlayStation 4, Nintendo Switch, and even mobile devices. Yet, for a specific generation of gamers, one question has never died down:
In the late 2000s, file size was religion. A standard PSP UMD ripped to .ISO was 1.2GB to 1.8GB. But our memory sticks cost more than the console. A 2GB MagicGate stick was a luxury.
Removing high-quality music or non-essential voice lines.
Compresses PS2 ISOs significantly without degrading game quality.
And that vacuum of official news created a monster:
Not what you’re looking for. Avoid if you want the over-the-shoulder action.