A little bit into the game, we can customize our characters. I pick a female luchador, with a no-nonsense voice, and my friend goes with the silver surfer.
The game systems are solid, the side quests are a-plenty (although we didn't do any of them).
The crit path is an engaging story, with enough of a plot to keep it going, even if the direction is once again, over the top.
The writing is excellent, and the voice actors were great. The voice I picked for my girl was awesome. The voice of random NPC #73 that I almost ran over is also good. The fact that there is also a cheesy movie plot you can do where the voice acting and script writing is terrible was also very enjoyable.
The controls are solid. My friend played for a bit on the 360 controller, but I just stuck with keyboard/mouse so that I could snipe people more easily throughout.
The upgrade system is implemented well, always giving you something to spent your money on that's worth it. Gaining reputation allows you to purchase more upgrades, and you earn rep by doing missions, or just blowing up things in general. We found that taking a tank as the preferred vehicle of choice to get to a far away mission worked extremely well for this.
About half way through the game, we swapped out our characters for a new look. I'm now a Harajuku/hipster, and he's the Joker with a British accent. Hilarity ensues.
When I thought about what I would change on the game if I could, I honestly couldn't think of anything. There were a few bugs I'd like fixed (assuming they weren't intentional). Like not being able to call in a car in certain places on the map.
Needless to say, the game is over the top in every aspect, and was greatly enjoyable from start to end.