1) Add more tasks to the mission
2) Add more zombies or waves of zombies in some places
3) To make missions more terrible (the moment when a poltergeist appeared in the forest was the most chic of both missions, + the music that started playing at that moment was very atmospheric)
4) Add a mini-quest for assembling vehicles to the mission (for example: collect different parts from the car in different cities) in order to use this car in the future to escape from the map or to break through the ambush
5) Add a zombie infection timer to your mission. The vaccine will have to create yourself. Components of the vaccine will be in different parts of the map. Or find a vaccine in a secret place that will be very well guarded.
6) More dark ambient style music

CUP weapons and remove any and all vanilla weapons, skins, vehicles, etc. arrma's been out for 5 years now and we're tired of the crappy vanilla content.