The best parts are, as usual for Lego games, the voice acting and amount of characters you can unlock and play as, and with something like Marvel there's a lot of weird characters (I especially was surprised to see characters like Hit Monkey and Forbush Man)
The bad parts are kinda everything else. Story-wise, it's not as fun as the first Lego Marvel. The time-travel part of it is fun but a lot of the guest characters only appear for one level.

The open world feels much larger with more collectibles, more races and more sidequests but the races are honestly awful. Controlling vehicles is clunky, and when every race requires you to drive through ring checkpoint with a time limit between each while also making sure to complete the entire race under a certain time and earn a gold medal to unlock the character or other thing, it's frustrating to play. Not to mention that races are locked to specific vehicles, which you unlock by destroying or collecting other things around the world like rings of birds/fish or spores hanging on the side of walls.