This campaign is great! But here is some problem...

When I upgraded Bill's weapons to max level, he using a grenade launcher at one time and just discard it. But when it's discarded, the grenade launcher is not disappeared.
And after few (short) seconds, he just grab a new grenade launcher and do it again.

A few moments later, there is lot of grenade launcher on the ground. Too many. So now game just getting lagging because too many "objects". FPS drop has started.
After few minute(or seconds), now game is totally much lagging. I can't playing the game normally.
...And now game has been completely freeze or crashed.

Zombie was keep coming raid with no break-time, Bill was keep discard his own grenade launcher but he's grenade launcher is still usable, Midnight Rider's weird fire show skill is too laggy and risky because game crashed.

What have you done? What have I missed? What a mess in here?
Actually this map is great but maybe someone who author they should fix this problem.