The new Marvel movie is an incredible display of juggling. That middle sequence (where the heroes split up to retrieve different stones) was really reminiscent of the original Star Wars for me. Had that same kind of spirit of adventure and quick pacing.
The only critique I had that they didn't really identify the heroes when they appeared. Every time there was a new one, you'd hear a bunch of whispering around me of people trying to figure out who is who.
Also, I really appreciate the choices they made at the ending. They didn't belabor it with pounding music coaxing you to cry, they didn't do the long slow-mo scenes of people wailing as their friends disappear (as the music swells in the background). It just kind of happens and they are left in shock. I appreciate more and more when filmmakers hold back from doing the typical shit.