Well I'm currently stuck on what I suspect is the final boss fight, which is every bit as annoying as Solidus from MGS2. Suspect I'll be stuck on this one for hours :/
But anyway... some thoughts. I started with MGS2, then 1, 3 and finally... finally! I've waited a long time to play 4, you know
This is the first game in the series that's left me in two minds. Am I disappointed? I think I might be. On the one hand the experience is very cinematic, but on the other hand...
*the ratio of cut-scenes to play segments is about 4:1. You have to press 'skip' about 3-4 times if you are skipping videos to get to the next playable bit (you find this out when your last save was a while back, and you choose not to 'continue' because you screwed up quite badly).
*the plot is nonsense. Yes I know MGS isn't super realistic - it's fantasy. But this plot is just nonsense, even compared to its predecessors. It's actually just ********.
*it's started to recycle rather heavily from previous games.
*the characters and events have become totally unbelievable, because they're so intertwined with each other now, it could only make sense in the mind of its creator. It's become like a children's cartoon. Each episode set up so the main characters can fight each other, over, and over again... Only now they're all related to boot. All the characters are one big (un)happy family now... it's bizarre.
*the bosses and boss fights are probably the worst of the series. And the first two are terribly easy to cheese by using the environment too. Easy to find places you can hit them with impunity. So easy, because the bosses get stuck behind door frames or other places where you can shoot them but not vice versa. That said, the last two BB fights were more interesting.
Overall, you play MGS mostly for the weird and wonderful story. The game is just like a bonus. But although this story is supremely well told, and beautiful to watch, the story itself is something of an failure, really. And the lack of actual playable sections is frustrating.
I can't give it a rating, because it defies any known scale I could grade it by. But very seldom does a game leave me with such mixed emotions.