Very good, but choses to miss greatness (EDITED after 2nd viewing)

Rating: 8/10 (25 April 2018)

EDIT after second viewing today.
I liked it a lot more today, mainly because I saw the movie for what it is, and not for what I intended it to be.
I could easily change my score to a 9/10, but it probably would not be fair.
Undoubtly stands the test of multiple viewings, very good movie overall.
The board was set, the pieces were ready, but an unfortunate lack of ambition and commitment prevented this movie from living up to the marketed premise, thus failing to deliver the much needed and desired ten year emotional punch.
It's still a very good movie, in its own merits.
The very best action scnenes, the jaw dropping cinematography (Imax 3d showcase!), a beautiful and emotionally soundtrack.
The movie tries its best to handle the various groups of characters, but clocking at 150 minutes, there is only so much one can fit in.
Precious minutes are sometimes wasted in rather poor and awkward atempts of comic relief that overstay their presence.
Some characters do not get enough screen time, it was never going to be easy to fit everyone in, but there were clearly questionable decisions, pacing problems and unwanted discrepancy.
Thanos character is one of the highlights, and is handled quite nicely, although his origin has been cut from the movie,
Even so, we can clearly understand what and why he wants to do.
One of the very best Marvel villains.
As it also happens in the comics, Thanos shows a lack of competence in handling his growing powers, being seemingly allmighty in one scene, and a juvenile brawler in the next.

This movie did not fulfill my - high! - expectations, and it's sad to know it failed to do so due to a "creative" vision that fell short of the ultimate ambition the movie required.
Anyway, still a pretty good superhero blockbuster, one of the better Marvel films (not on the very top tier, though) and highly recommended to not only comic book nerds as myself, but also to the general fantasy/action/sci-fi movie audience.
8/10
(as a long time Marvel fan, I truly wish I could rate this movie higher, but honestly and sadly.... can't.)