oh man, i just got it for PSN, and the map sure does get tiny when you get far apart. i'm sure its fine if you follow each other around, but that's not a very efficient way of playing the game a lot of the time. i was expecting them to split the screen when you got far apart, but no, it becomes unplayable instead as its zooms out. can't see things like bats for instance (and I play on a huge projection screen). guess you gotta really factor in distance if you want to try to take different routes to see if its feasible to do so. or clear all the enemies first together, and then have the other guy go to the other location to activate some switch or whatever while you wait.
on the plus side, if I want to see what a dual crush looks like just by myself, i can easily enough play multiple players by myself.