Ok, I'm posting this based on seeing tonnes of negative posts about this game, particularly from fans of the 1st instalment. There's 3 reasons I think why this has happened, and how i think you should approach if you play it.
Reason 1: The 1st game, set the bar too high, not just for this series, but for video games in general - it was phenomenal and every other positive word that you can think of. It was going to be hard for Naughty Dog to install new features as they covered every inch of detail in LoU1.
Reason 2: (without giving away spoilers) Naughty Dog made a HUGE decision regarding one of the main characters that I can respect some fans won't, and ever will agree with. It was a kick to the crotch to say the least, but if you can see passed this and understand why they went down this road, it's easier to carry on enjoying the game.
Reason 3: It also made another risky decision to play 2 parts of the main story at the same time, with one of them being new enemies of the characters of 1st instalment. Fans of the 1st absolutely adore Ellie and Joel, so it's quite loyalty testing to play this way and I respect those that couldn't come to terms with it. I sort of liked this dynamic, however, i think it resulted in the overall game becoming way too long-winded and it's the main reason I can't give it 5 stars.
Positives:
LoU2 is still a very enjoyable instalment in my opinion, it still has all those fluent and flexible gameplay features that the first had; easy to move, change weapons, shoot, hide - multiple types of human groups and creatures to develop strategies against and you can opt for stealth or a more hands on approach.
LoU2 still has great stories and intriguing characters and a great insight into how a world would exist so many years or if such a pandemic occurred.
LoU2 still has exciting settings, including a sort of 'open world' section with a few extra nuggets if you explored it hard enough.
If you do play this game, and particularly if you're a fan of the first. Try to keep an open mind about the plot, and probably avoid stealth as much as possible (yes, hard as I think stealth is a beauty), as the glameplay very very long and stealth only adds to that.