Powers wise they are pretty much identical with the second adding a couple things, like the wing suit ability that let's you glide but I never thought it was that great of an ability.
A friend and I played through both recently again, they are fun in their own ways. The first is a little more focused with the bosses to defeat, agent cars upgrade as you level, points to take on the map so you can spawn, orbs are easier to collect generally. The second gets rid of the bosses and brings in the zombies, a lot less focused as you can generally do as you please and spawn where you want iirc, some extra abilities, helicopters, a literal fuckton more orbs to get, but it is the exact same city with some changes.
I think my friend and I enjoyed the first more generally, we spent hours in the stadium just rainy around in cars trying to do flips, or doing the races in the big trucks which could never drive up stairs properly. But that isn't to say the second isn't enjoyable, if you can get a friend to play with I would suggest playing through both, they can be a lot of fun.
