I'd start placing your bets on a Metal Gear Solid Master Collection Volume 2, as a datamine in the first volume certainly points to a follow up.
When you title something as being "Volume 1," you'd certainly think that that would mean a Volume 2 could be coming somewhere along the line. Metal Gear Solid Master Collection Volume 1 just released (it's alright!), but it doesn't contain all the main games, just the first three, as well as the NES Metal Gear games. That of course implies that at least MGS4 and 5 would be in a second collection, and based on a datamine shared to Reddit earlier today, that certainly seems quite likely.
A couple of images were shared with the Reddit post showing some code with text that makes reference to both MGS4 and 5, as well as Peace Walker, a PSP entry in the series that was released in 2010. The references aren't much more than that; they're just listed out as acronyms, with nothing much else to them. But other than just having them listed there for a laugh, I can't see any other reason as to why they would be other than the fact a Volume 2 is in the works. It would be an absolutely wild decision to subtitle a remaster collection Volume 1 and not release a second part, but Konami isn't exactly known for its typical business decisions (I'm looking at you, Metal Gear Solid 3 pachinko machine).
If MGS4 is included in a Volume 2, it'll mark the first time the game is playable outside of its release on the PS3, as with Volume 1 all other entries are playable on modern hardware.
Of course, this whole remaster is just a way to get the series back into the public consciousness, as it has been a while since we've had a new release. Plus, it's a good way to kill some time while we wait for the MGS3 remake, Metal Gear Solid Delta: Snake Eater, which doesn't currently have a release date.
Related Forum: Gaming Discussion