Whether local split-screen co-op has made it remains unknown. Peace Walker has adopted 60 frames per second from its origin on PSP to the HD consoles.
The Metal Gear Solid creator said via twitter that "4 people can co-op and it is 60 frames. During loading, characters’ dialogues pop up at random." The remake is part of the Metal Gear Solid HD Collection which includes MGS2, MGS3, Metal Gear 1 and 2.
If you opt for the Ultimate HD Collection then you also get Metal Gear Solid 1 and Metal Gear Solid 4, but that's only on sale from Zavvi for the PlayStation 3 for £69.85.