I haven't played 4 or 5 since I don't own a next-gen console. The OG MGS has the goat bosses, story, and atmosphere, bu I think 2 and 3 have it beat if we're going PURELY on gameplay and nothing else. Yeah, Snake >>>>>> Raiden, but the improvements with the overall gameplay and the guard AI in those 2nd and 3rd games are just
* You could hang off of ledges and shimmy across walkways.
* You could roll into enemies or into a crawling position.
* You could hide in lockers to avoid detection.
* You could stuff your enemies into the lockers after knocking them out or killing them.
* You could aim in first person
* You could hold up guards and take their stuff.
* 2 and 3 gave us nonlethal weapons like tranquilizer guns, etc.
* Choking guards out was actually a viable tactic.
* 3 also gave us CQC, including the ability to slam enemies and interrogate them for info.
* MGS3 gave us the ability to poison guards with rotten food.
* In MGS3, you can also distract enemies with dirty magazines and empty ammo clips.
All these tactics you couldn't use in the OG game.
(I know a lot of this was retroactively added to the Twin Snakes remake, but they messed up by not redesigning the levels with these abilities in mind, since having all of those new moves and abilities in the first one makes everything way too easy.)
On top of that, the enemies in 2 and 3 were a lot smarter.
Yeah, they still investigated out-of-place boxes and followed footprints and suspicious noises like in the original, but in addition to that:
- they'll use their radios to call reinforcements if they see, hear, or even smell anything suspicious.
- If they see dead bodies, they'll kick it up to maximum security and call for reinforcements.
- When searching for the player, they'll summon whole squads to check every nook and cranny of the level. They use actual tactics, even setting up actual positions to spot and ambush you.
- When attacking, they'll try to flank you and cut off your escape routes. Some of them even come in with heavy weapons/armor and riot shields.
- If they know you're hiding under something, they'll toss grenades under there to flush you out.
One can argue that the other games were better when it cames to bosses, music, the storyline, and the atmosphere, but IMO MGS3 has the GOAT stealth gameplay and the best tactical depth out of any game in the series. I suppose you could put MGS2 up there as well.
Snake >>>>> Raiden as a character, but the overall advancements in the gameplay between that jump from MGS1 to MGS2 was nothing short of amazing. And that's no shade against MGS1, because it's still a classic and one of the absolue best games ever made. I just wish there could have been at least ONE more game about Solid Snake in his prime before Kojima left...