I am slowly and occasionally playing through MGS5 and I mostly like it. Mechanics-wise it's by far the best MGS. The setting is also great and it's a really nice touch that the NPC's are actually speaking their own language.
In any case, Metal Gear Solid is now a open-world RPG, or Grand Theft Auto set in 80's Afghanistan. You recruit soldiers to your own base that you expand and you can have the soldiers scout the areas you are working in, research new and better gear (that part is HUGE!) or send them out on their own missions.
The controls are a lot like MGS4 but the endless cutscenes of that game has been switched out for a lot of radio-talk. This is probably my biggest gripe with the game. Yeah, MGS4 has too much cutscenes but there's barely any left now. The franchise has been heavily story-driven since the first Metal Gear Solid and it's just sort of gone. I mean, there is story but you usually have to play for hours to see five minutes of plot. Again, the game is a blast to play but I often find myself not knowing what I fight for except for improving my army and my gear. What pisses me off the most is that when they focus on the story it's really good and I wish there was more of it. Now I just play a few hours here and there to not burn out on the endless stealthing. AGAIN, the stealthing is really good but it's all you do and without a real plot to drive you forward I tire after a while.
But on to the most important thing, you can have a buddy tag along on your missions and one of them is a wolf with an eyepatch!
His name is DD and he is a good boy, the best in fact! DD marks your enemies and has perfect stealth so he's never a nuisance. It's also a blast for some reason to have a big, happy dog tag along you on missions with international importance. I can't help caring about the big lug, if any soldier ever acts aggressively towards him or even tries hurting DD I will stab that son of a bitch in the fucking heart!
DD can do more things like confusing enemies and you can even equip him with a big stun-gun so he can take out enemies by himself. But the most important thing is that you can have a big, happy doggie with an eyepatch!