Not the worst Marvel movie surely. A decent watch. There are a lot of Marvel movies way worse than this. I liked the fact, it had a bit mature tone to it. They tuned down the comedy a bit. I liked that. Marvel movies were leaning towards too much unnecessary comedy. Great visuals. A good introduction to the galactic level threats.
But it's just too many characters they're asking you to care for, in a short period of time. So, you end up not caring for most of them.
Still, pretty enjoyable.