Finally comes the news that the Master Collection won't support keyboard and mouse. Konami launched and then took down the game's Steam page but, for the brief period it was up, it contained this text: "Notice: Metal Gear Solid–Master Collection Version requires a controller in order to play. Playing with a keyboard and mouse isn’t supported."
Makes me wonder if these versions are going to have any advantages over just emulating the originals, and MGS1 and 2 even had official PC releases with fan mods to patch them.
There are some pressure sensitive controls in, at least, MGS3 that relied on the dualshock's capabilities. I assume there will be adjustments to that. It was a barrier when I tried to emulate it.
I think it was the triggers. There are definitely ways to make steam gear work. I didn't mess with it too long, because I was just experimenting with steam deck emulation to see what would run.