It's not complete, but it covers most of the bases - my Metal Gear Solid collection!
Metal Gear Solid (PS1) / Metal Gear Solid: The Twin Snakes (GC)Twin Snakes was my second MGS game and is actually the only version of MGS I have played - while I own the PS1 game, I've never played it! While people may argue the game is made too easy by making use of the MGS2 engine and game mechanics, and the cutscenes are turned ridiculous by Snake's superhero-like flips, I think Twin Snakes is a very worthy remake if only to hear Psycho Mantis talking about Super Mario Sunishine and The Legend of Zelda!
Metal Gear Solid: 2 Sons of Liberty (PS2) / Metal Gear Solid 3: Snake Eater (PS2) / Metal Gear Solid 3: Subsistence (PS2)MGS3 was my first MGS game and is a great introduction to the series, standing alone well enough as a prequel but still tying in heavily to the overall series. For my money it's also the best game in the series, and one of the best games ever made. Subsistence is interesting for adding a freely controllable camera, but with the original game designed so well around its fixed camera angles I'm genuinely unsure which I prefer. Both are different, and valid, experiences of the game!
MGS2 is the most artistically accomplished game in the series with its post-modern plot, frequent fourth wall dismantling and the player insert main character of Raiden replacing Snake. I've only played it through once, in the run up to MGS4's release, and it's definitely worthy of me revisiting it someday soon!
Metal Gear Solid HD Collection (PS3) / Metal Gear Solid 4: Guns of the Patriots (PS3) / Metal Gear Solid V: Ground Zeroes (PS3)Not pictured - the giant box from Zavvi that the HD Collection came in. I still wear the t-shirt it came with to this day!
MGS4 was the game I bought my PS3 for, the first home console I bought with my own money. I first played it through on a 14" CRT, unable to even make out how much ammo I had remaining for my gun - and it was worth every penny! It was also MGS4 where I most got into Metal Gear Online with probably the best iteration of the multiplayer.
Ground Zeroes is the prequel to MGSV proper and by my reckoning the best part of MGSV. While MGSV slightly refines the gameplay (impressive, considering how well refined it already is in Ground Zeroes), GZ has a better realised and more focused sandbox upon which the game is set. It's a short experience, but one of the best! I also posted some pretty high speedrunning times on the online leaderboards...
Metal Gear Solid V: Ground Zeroes (PS4) / Metal Gear Solid V: The Phantom Pain (PS4)Of course I re-bought Ground Zeroes on PS4 (unfortunately with a very stubborn pre-owned sticker ruining the box!) in the lead up to The Phantom Pain's release. The story of MGSV is well-told, in many respects an incredible game but also suffering greatly from being unfinished. Funnily enough, it's also the only MGS game that
I haven't finished! I do intend to fix that one day.
Metal Gear Solid: Portable Ops (PSP) / Metal Gear Solid: Portable Ops Plus (PSP) / Metal Gear Solid: Peace Walker (PSP)Portable Ops (and its expansion Portable Ops Plus) are good handheld spin-offs with some notable mechanics, but Peace Walker should be considered right up there in the mainline series. MGS5 in all but name, Peace Walker is an incredible achievement on PSP hardware, a brilliant game in its own right, and set the direction for a mission based structure that MGSV would later follow. It's arguably one of the best MGS games!