Been playing it a bit, pretty neat idea really. There's some nice tension between wanting to PvE and fight the monster(s) for rewards and wanting to PvP and/or not get PvP'd once you have your monster loot.
Map is really well detailed, but there's only the one map that I've seen. Normal enemies could be a bit more threatening and I wouldn't complain. The only even sort of dangerous one right now is the hive, and that's only if it's under a bridge or inside a room or something and the swarms aggro you through terrain or walls. Everything else you can just knife/melee to death with almost no risk.
Progression system seems a bit questionable, as so far all the unlocks past level 15 or so are just better versions of existing guns. Like, new lever action rifle, but it does 40 damage instead of 35! Not only very boring, but means the match making better be spot fucking on so lower level people don't get roflstomped by superior weaponry.