i don't know if iZone already have this or not I just post what I think
a shooting arena
at iZone we can shoot at all direction right?
so,inside the building there will be 2 or more arena(I would like circle shaped and make it little big) each arena have diffrent difficulty
so this how it works: when u start (entering fee 50$) the arena timer will start begin (1-2 min) and enemy will start attacking and you need to defend yourself!
each enemy you killed you will earn money(5-10$) u will earn the money you collect if you survive after timer end
but,if you died before timer end you only get half of money you get by killing enemy
(the harder arena u enter the entering fee and money each kill will be higher)
well,that all I can think maybe there are some staff that would adding more
sorry if there anything wrong with my post