I find Metal Gear to be a really odd animal. On the one hand, MGS for Playstation absolutely blew me away. It was incredibly cinematic and more clever than any video game had any right to be. Events like the confrontation with Psycho Mantis left an impression that sticks with me to this day. On the other hand, I find it incredibly difficult (and incredibly stressful) to stay "stealth" for any length of time. Much of the game (and every subsequent game in the series) boils down to: OK, there's a bad guy. He can probably see me if I move now, let me wait a moment... just a moment... I think I should be OK... now! Oh fuck I've been spotted time to run around and try to take cover or retreat to wherever there are no bad guys...
When you add features like the ability to take dog tags from enemies by sneaking up behind them, then I realize I'm not anywhere near as patient as I thought I was with video games. Again, MGS is easily in my top ten games of all time, EASILY, but it's more because of how groundbreaking it was and how it redefined what I thought video games could do. Even though, technically, subsequent games in the series improved on the formula, the "holy shit how fucking cool is this" factor wasn't as strong any more and I just found myself constantly getting frustrated whenever I lost my cover. Maybe I'm just better suited for Mario games, but I find myself less and less enthused by new Metal Gear games (I haven't played part 4, and I didn't make it halfway through 3).
I hope part 5 does well, simply because I think Kojima deserves as much success as the public is willing to lavish him with, but I'm well past the point where I'll be first in line for another Metal Gear game, only to once again feel the repeated frustration of being spotted by a bad guy I either didn't know existed or believed wasn't able to see me.
