I've only just played it recently, and I give it a 4/10. I want to like it, but I just can't... there's just way too much wrong with it.
The story is beyond contrived and just a chain of nonsensical action scenes. Many events make no sense to me as to how or why they happened. It feels like they tried to go global for this epic feel, but made it so stupid in the process that you can't suspend disbelief. A gas that instantly zombifies people, but our characters are running through it almost continuously is ugh. Blind siding avalanches. A Nemesis that is trying to dismember you in the start, but when it gets it's foot on you, is happy to have you walked away to be a captive for whatever reason... None of it makes any sense.
The intertwining scenarios is a good idea, but I really wish they would return to one character rather than this buddy system they seem to be pushing these days. It thinned the story way too much having to tell backstory of all these new characters, + the main plotline, + continuing the characters we already know. Quite often I felt like I was just running through tunnels, with no idea wtf was going on or why.
Maybe it's because I played solo, but the gameplay felt weak. I can imagine that if you are playing with a human partner it's a lot more fun, as quite a few of the scenes seem very well crafted for two human players to work together in. But solo, you just end up being victimised. Getting chain knocked down by bullets and snipers is beyond infuriating at times.
This was especially prevalent in scenarios with machine gunners or helicopters. Where one person should be distracting while the other shoots, it became almost impossible playing solo when the things were aiming at you for over 90% of the time.
The punch to the chest to revive you is also lame as hell, and when it does work, being stuck in half death without any herbs and not being able to utilise your melee attacks made me wish I was just dead and could restart.
General combat was a bit meh. The moving laser reticule was more annoying than challenging. And quite often I found myself going into 'cover mode' behind a wall without wanting to and not being able to come out of it. This system seemed completely pointless, especially since most of the enemies just run straight up to you anyway.
Some of the boss fights felt weak and unpolished, like the helicopter with Jake/Sherry. I had to sit and wait for Chris and co. to shoot it down because the game didn't provide me enough explosive ammo to help. Then there were bosses like Helena's mutant sister, which felt like I didn't even need to be there. Before I could get a shot off, the thing had already moved on to its next phase.
They tried really hard to give horrific deathscenes, but most just went on for way too long, like the leech man impregnation.
The item system was clunky and awkward. Throwing grenades is crazy annoying. And having to put herbs in the pill pot to chug was a pain in the ass, especailly when the game doesn't let up for a second to allow you to sort your bags. There's also not enough space later on in the game. It's great that you can carry every gun, but when you can't pick up the damn ammo because you've barely got enough room for one stack for each weapon on top of all those useless grenades...
Didn't like the QTE's. Admittedly, I was playing it on professional from the outset, but many of them seemed pointless and required knowledge that they were coming to have a realistic chance to hit them. Especially when they wanted precision timing. I also hate anything that wants you to twist the joystick... it's just not necessary and it doesn't make you 'feel' like you're really turning the handle.
Which brings me to the controversial cutscenes. Now, I don't mind cutscenes, I actually like them. Give a piece of believable action that introduces the big bad guy or his wave of minions... that's great. But the amount of ingame cutaways to inform you of a new event, an extra one guy falling in through a vent, a door timer, or just the bloody shutters on the windows closing, all the while enemies are still in the room is beyond ludicrous. Worse still, the bad guys don't appear to stop moving like the players do during these events. The amount of times the game cut away for a pointless piece of scenery, only to return my control with the thing I was aiming at standing right next to me and instantly pouncing is just...
To give some positives to show I'm not completely a negative nelly. I was very impressed with the range of enemies. Were it not for the guns, the evolving Ja'vo were fantastic. So many great insect variations. The super coccoon monsters were also legitimately frightening and a good difficulty level up from their minion counterparts. There were also a number of puzzle gems thrown in there--notably the one to work out the cell numbers in Leon's campaign.
So yea, that's my review. From a solo playing experience, the bad just far outweighs the good. I don't personally mind the more action based direction the series is taking, but if they really want to push the partner system, then start designing the games as online play only, because the AI will never be good enough to give a solo player a satisfying experience. I think I spent more time in this game being incapacitated than I did shooting mutants.