Because emulating those features unfortunately is a bit more heavy duty on modern graphics cards, especially at higher render resolutions.
A patch for the PSP game is unlikely, but I think I've heard the PS3 version can be made to play in PPSSPP (since it's an HD remaster.)
It might be possible to create an HD texture pack (but PPSSPP doesn't yet support these), but for legal reasons I don't think it could use the PS3/PC version's assets. That being said, I'm not a lawman nor do I even play one on TV.
-[Unknown]
A patch for the PSP game is unlikely, but I think I've heard the PS3 version can be made to play in PPSSPP (since it's an HD remaster.)
It might be possible to create an HD texture pack (but PPSSPP doesn't yet support these), but for legal reasons I don't think it could use the PS3/PC version's assets. That being said, I'm not a lawman nor do I even play one on TV.
-[Unknown]