I'm actually rather happy with just police. I'd rather see civilians doing more, actually. Possibly placing markers ("Safe Zones") that make all civilians in the area go into that neighborhood or house, because I found a neighborhood on Leicester that you can defend and keep about 100 civilians alive, but they just slowly migrate out into zombie infested zones and get eaten. More objectives too, and maybe gun shops that civilians in the area go to and grab a weapon? I do hate how the civilians without guns just wander around while zombies take over the street. But these are suggestions. 4/5 for not being lastingly playable, survival gets boring, (Yes I know, its the beta.) and the mission mode is fun for about 3 times, then it just kinda gets "Meh"
you just gottas keep playing till the boss is in a bubble. the game system is designed so that you must kill a number of enemys or must play for a certain amount of time (im not very sure) before the boss shows up.