Haha thanks so much for the feedback Supersmo! I really appreciate it. Me and a couple of friends ended up getting so far on one run that some of the enemies stopped spawning so it's possible to actually 'beat' the game in a sense - I'm planning on doing an update to the game soon to try and balance it a bit better, iron out the bugs, add coloured trails to the players - and as you mentioned, fix the deadzones :)
Guess me and my kids will have to practice some more then ;-)
Glad to hear that you plan to fix these glitches :-)
(Posted about Defend The Night in a Steam discussion thread about games for more than 4 local players: http://steamcommunity.com/groups/morethan4localmultiplayer/discussions/0/1546440... )