This game is ridiculously fun.
There is a sidequest later on where one of the survivors asks you to take her picture, and you can get a bunch of high-scoring Erotic photos out of that one.
I got the Real Mega Buster a while back; now I should try for the Real Laser Sword. That's going to be a bitch, though.
A couple of tips that I haven't necessarily seen elsewhere: [HIDE]Once you kill the clown boss near the amusement park ride, his small chainsaws respawn. That plus the entertainment/engineering/criminal magazines mean you should never have to carry any other melee weapons. Those plus the RMB make the game almost too easy.
Also, if you want to skip the main story for whatever reason, go through the stuff in the entrance plaza, but stay there until after 5 p.m. game time. Then when you go through the warehouse, you'll get the Queen cutscene instead of the Jesse cutscene. You'll still get the sidequests, but you can do things like go for the Zombie Genocider without having to worry about the main missions. (Actually, you can also do that just by doing something like letting Brian die instead of helping him out, and just continuing instead of quitting.)[/HIDE]