Simply the most original take on a franchise that only mildly re-invented itself upon each release.
Then MGS5 is released and it massively reinvents itself for the better in every aspect. Its open world. Both maps are huge. It can be played full stealth, full out third person shooter mayhem or a combination of both.
A brilliant game engine, an insane attention to detail, infinite replayability, a sense of humour, coupled with an eccentric and fun story just lead me to conclude that this is the open world game design other open world games need to emulate. Theses a Base building section, you recruit members for your covert army from enemies you defeat. Do you like that tank the baddie is using? Airlift that sucker out and now its YOUR tank! Raid outposts and bases for materials, save the wildlife in the war zones if you want, brutalise the enemy, or take want you want and vanish like a leaf on the wind. It's truly an open game.
With 50 story missions which can sometimes take hours ( if you want them to), and around 175 side missions ( all but a few are optional), this game is worth its asking price.
If you like open world games, this is for you. I simply cannot give this game enough credit for its brilliance.
But it now, and be prepared for a wonderful all encompassing experience, that, at this time, I can not ever see being equalled.