What people seem to be missing here...

Rating: 10/10 (26 April 2019)

I'm giving this movie a 10/10.
What I think a lot of people are missing when rating this movie so low is the fact that it's obviously going to have a different tone compared to Infinity's War. Endgame starts with hope and then is immediately shut down when Thanos admits to destroying the stones. So yes, it's going to be less "energetic".
Certain characters are going to be handling the situation differently as well. Let's take Thor, he's completely and utterly defeated. He could have stopped Thanos in IW but didn't. So he's going to be self-destructive. Sure he was made into comic relief but he always was (let's be honest). And if you know the marvel universe at all you'd know captain America wields the hammer since he's worthy (apparently that was hard to understand). OH and did you know in the MCU/DC crossover in the comic books superman does as well??
Anyway, I think if you gave yourself high expectations you wouldn't enjoy the film. Go in with an open mind and it'll be just as amazing as IW. You'll feel like a 6 year old watching your favourite cartoon crossover episode on a Saturday morning.