Character moments would be Harry's argument with Peter at the party being less confrontational.
The rest all action.
Nah, there's more:
From a review: (which I don't agree with as I prefer the extended simply because of extra Spidey)
The first added footage comes when Peter arrives at the pizza shop. We get a few more seconds of material when he discusses his job with his boss. We find a tiny amount more between Peter and the usher, and there’s an alternate version of Spidey as he takes the elevator.
A totally new sequence shows MJ as she discusses her relationship with John Jameson. We also get a fully fresh clip in which Peter attends Connor’s class right after MJ’s play, and another piece shows Jonah Jameson as he wears the Spidey suit. As for extended bits, Peter’s visit to Student Health runs longer, and we see more of Peter’s birthday party. The first fight between Spidey and Ock extends, as does the train battle.
Does 2.1 improve upon the theatrical edition? Nope. It works just fine for what it is, but I think the original version stands as the superior rendition. For a big fan like me, it’s fun to see the extra scenes. They just don’t add anything to the experience.
Indeed, the new sequences occasionally slow down the flick a bit. Take that alternate elevator piece. While the original was tight and snappy, this one drags. It’s fun to see but would be most interesting as a separate deleted scene, not as part of the movie.
Probably the most substantial sequence comes from the part with MJ and her friend as they discuss whether Watson loves John Jameson. This tells us a little more about MJ’s relationship with John but doesn’t really expand our understanding of things. Even without this bit, we already know she loves Peter and not John, so the scene is fairly redundant.
The additional footage in student health comes across the same way. It delves into Peter’s psyche more but doesn’t actually tell us anything we don’t already know. Again, it’s neat to see but deserved to be on the cutting room floor, as it slows down the story.
In the “funny but indulgent” category comes the part in which Jonah Jameson dons the Spidey suit. This is cute but undercuts the character. It implies strongly that Jonah idolizes Spider-Man, which isn’t what we want from the character. He’s much more fun when he fully despises Spidey, not when he indulges in a little hero fantasy.
As an alternate version for fans Spider-Man 2.1 offers a fun take on things. The changes don’t significantly harm the tale, as it still works very well in this format. However, I think the shorter theatrical cut offers the superior edition. It presents a tighter, smoother flick and remains the best way to experience the story.
