Basically, Ultimate Marvel is what the original should've been...but some things should've been left alone.
Well, gameplay is obvious the same for the most part. One of the main things that've changed is the strategy in the matches. Now, you have options to take away opponents' meters in air tags, activate X-factor in the air, and dashes are no longer followed up by blocks. Then, there's each character's buffs and nerfs. Some got new moves which are either useful or worthless. I don't mind the changes because it allows a bigger variety of tactics to choose from. And the new characters fit right in, though won't make the game completely balanced unfortunately. The newcomers are quite fun and unique to use. I also glad that many of them have humorous features. Phoenix Wright is my favorite since he is the most unique of them of all; He fights without really fighting at all.
The graphics pretty much look the same. A tiny bit better and flashy. There are new stages, though most are just the same with different backgrounds. The design of the HUD really bothered me. For one, the structure makes it harder to see your teammates' HP. Even it show which button is for each teammate, being used to the ones in the original can throw you off cause confusion. I kinda wished that they left the HUD alone almost completely.
The new features (or ones that should've been added a long time ago) are not bad. Finally, we get to watch online matches and see who are we up against rather than under or over-estimating opponents due to ranks while seeing license cards dancing during the entire match. I do like the fact that if connection is lost, you don't get kicked back all the way to the main menu. Though no Heroes and Heralds mode for now, I hope it'll add fun to the game for those who are new and those who just want to play around. Mission mode is back. And (most likely because knowing combos and stuff well) the missions are kinda easier, but definitely changed according to the buffs and nerfs.
I like the new characters' themes. Hawkeye's and Wright's are my favorites.
Ultimate Marvel is a good upgrade. Some things needed to be added or changed, but others should've stayed the same. I know that I am harsh on Capcom for pulling out another addition to the series, but I didn't want to waste more money on a game that could've been made months ago. It's still a great fighting game indeed. Just hope Capcom don't pull another stunt like this again...but they might.