I just ran through the intro level. This really is the epitome of a "AAA" game. Cut scene, cut scene, PRESS BUTTON, cut scene, button mash, more cut scenes, cut scene, do some stuff, cut scene, switch characters, repeat.
Thor seems OK I guess. Iron Man was kind of boring. Hulk was pretty fun, Cap was good, although there was a point where it kept prompting to press forward and hold O to vault over shield-bearing enemies, and he wouldn't do it because their backs were to the wall. Black Widow was also good and had better melee stuff than everyone else.
Visually it looks good, but also off. There's something about the character models that makes them look like they're from a high quality big budget PS3/360 game. I selected the performance option over 4K and it seemed pretty smooth for the most part.
Also kept getting these "YOU ARE NOT CONNECTED TO THE SERVER. CHECK YOUR CONNECTION" messages every so often. They cover the middle of the screen and are super-annoying.
Nothing about the way the game plays really stood out to me but Hulk and Widow were the most fun. Will keep going later.