Improving on the mechanics of Spiderman 2, but it it may have focused to much on improving the bad instead of losing it.
Another great improvement are that the graphics are amazing. They could be a little more crisp but they match the comic book flawlessly. The characters move more lifelike and there expressions are exponentially better than Spiderman 2. The voice overs are also great. It takes a little while to get used to the voices for Peter and Eddie since there are so many different versions, but you can step into the game and feel very immersed in the Ultimate Spiderman world.
Although almost every aspect of this Spiderman game is improved from Spider-man two many bad ideas werent thrown out as they should have been. The Civilian missions are better and more fun, but they tend to slow down gameplay instead of just happening or being an obvious progression in the storyline. Also, and this may be a personal oppionion, but I hate going through a guide to find 190 tokens, realize I missed one and go back through them all to find the last one. Collecting tokens is rationallized by some great rewards, but they are very frustrating.
Also, the trick races are unnecisary. The easy races are fine, but the later races that pit you against Johnny storm are not only unfair but some of the most frustrating moments in any game I've experienced. Spider-man takes time to get up to speed and he can't leap buildings in a single bound like would be much appreciated. In fact, there is no good way to get to the top of a building fast while still maintaining speed to chase an enemy or race the clock. If you get behind once catch-up is nearly impossible.
The bosses are memorable and much better choreographed than the previous Spider-man title, except you have to chase down nearly every villian you spot. The gameplay is as follows: Save 2 or 3 civilians, find boss, chase boss across entire city, fight boss, save more civilians. Chasing the enemies is alright, but it gets repitious.
One of the more reckless fun and guilty pleasure elements of the gameplay is of course Venom. The ability to play as Venom in depth for the first time in a Spider-man series. His mobility is polar opposite of Spiderman which gives him quite a different feel that makes gameplay much more interesting. His vertical movement is ten times better than Spider-man although his horizontal movement isn't quite as great. The only improvment I could see neccisary is for the lock on when tossing cars. It's easy to tell where the car will go, but it's difficult to aim it at anything in particular.
Overall the game is a great improvement and I suggest that Spiderman fans or just Marvel comic fans in particular should check this game out. It may not be perfect, but it has it's excellent moments. I reccomend.