The lights are on
1- If you are unfamiliar with first person shooting games start on easy, but if you are familiar, start on hard because it is not really hard and it is quickest to get used to the game
2- Your weapons: always have a magnum, it is your best friend in the game; it makes wonders. with one shot you kill multiple zombies and quick to reload. While downed, your magnum could save you and save your friends. Always, have an auto-shotgun with your magnum but use it only at need such as when a special infected shows up or an ambushed, otherwise use magnum and keep your shotgun at reserve.
melee weapons: Amazing and powerful, and could save your life if cornered or bombed. Choose wisely, you could have a magnum or melee weapon but i would recommend a magnum.
Pistoles: NEVER use them, two of them or one; never ever have them
machine guns: also, could be combined with magnums but still the auto-shotgun works best.
3- if playing on expert: save your health kit as long as you can, rely on pills, and always have a shot at reserve instead of pills; shots are life saviors, you never know what you desperately need to use them. Also, if you see pills, shots, and health kits and do not need them, then do not use them, you never know when you may need to come back; but if you know the game does not llow you to come back for them, then use them.
4- always have one of ur friends having a molotov for the tank, otherwise if you already have killed the tank, have a pipe bomb, it is a life savior. For bile bombs, always save them for the hardest part of the campaigne where you have to run to the save room and never waste them on a tank or to clear zombies because zombies with respawn.
When to use pipe bombs? if you think you can not handle an apocalypse, use the bomb- do not save it until you die and restart. also, use them if you think it takes a lot of time to clear the area and do not want to wast time.
5- How to avoid being hit from zombies that you do not notice? Always and always have a wall or anything protecting your back if possible. Corner your self to shoot un-triggred zombies and those triggered. Have a plan for the next secs, do not run without planning for the next few feet. If cornered use your push button wisely because it depletes; mix between magnum shots and the push buttons.
6- cooperative play- always, watch over your friends, their safety is your safety. If their health is reducing give them pills, and if they have 1% heath a shot would work too but start giving them pills first. If you all desperate for health, use your judgment when giving health to someone, give it to the player you think will save your butt and the not the one you have on your friends list. On expert, kick those who fall down every minute, they are not worthy. also, kick those who shoot you by mistake frequently, those are your worst enemies. kick those who use health when not needed also.
7- For the last part of each campaign when you have to hold out, always know where you gonna be holding out you and your friends before triggering the apocalypse. and always save Molotovs for tanks, biles for running to the rescue, and pipe bombs when things get out of control and need to collect yourself. Have one friend luring while others shooting at it.
At the end, use your best judgment, this a personal-best judgment game