I don't think that there is a word that can describe how incredibly unbelievable this game is!.
WARNING: THERE MAY BE POSSIBLE SPOILERS (MINOR) IN THIS REVIEW.
This game is about Solid Snake who is now old due to accelerated aging (cause unknown). He has to terminate his rival Ocelot who has been taken over by snake's twin Liquid's arm. Liquid has something evil up his sleeve (play the game to find out what) and snake must stop him. Story sounds real simple but firstly, there are probably a dozen or two twists and turns throughout the game. Then, all and i mean ALL questions that you had about things in the other games (Patriots, FoxDIE, etc.) will be answered so its a real relief. thats all i will talk about the story or else it will be ruined.
Now the gameplay. Everything added from previous games such as aiming and cmo has been refined. They are perfect. Then the new additions such as rolling, walking while crouched, moving while aiming and new weapons and items have made this even more fun to play then ever. With other MGSes, i would only play to find out the story but now i love playing. The graphics and sound in this game are perfect. There are also awards for certain things adding replay value. (im on my 2nd playthrough now). Dont believe me, check out some vids or go to futureshop and play one of the demos.
Now the final part that makes this game unbelivable. METAL GEAR ONLINE!!! IT IS AMAZING but I wont talk about it because if you still aren't compelled to buy this game after what i talked about theres no point (also its 2 am and im exhausted).
Well there goes my review for the greatest game ever made and i just have to give Kudos to Mr. Kojima.