- When you are inside a safe zone, time is your friend. You can either sleep until morning in which case the hard zombies like night hunters/stalkers disappear entirely. Or you can just stand there for a minute in which case they run off and forget about you.
- Out in the open, time is working against you. No matter how tough you are eventually you will attract a bunch of biters and volatiles (tough, fast, jumping zombies) and they will overwhelm and kill you. Shooting guns will speed up that process, as will setting off your own explosions, or using a molotov on a red barrel. Surprisingly, lots of melee combat also qualifies as noise and will slowly draw more & more enemies to you.
You will never be inhumanely powerful in this game, and always subject to a quick death if you are careless.
- Make good use of your limited time before you get mobbed. Running past enemies is preferred during most main and side quests. Quietly killing one and retreating will extend the time before mobs show up. Take the skill that lets you instantly kill an enemy when you are behind it.
Smart use of an explosive will kill enough enemies that you can loot boxes or get your head together and escape. Poor use of explosives doesn't kill many enemies and just draws a ton of them to your vicinity.
- Taking the camouflage skill works a lot better than UV flares or firecrackers when you need more time. Especially with the Takedown skill. You can nail one enemy, camouflage, do some work, takedown another enemy, and just keep on working. Bear in mind you need several seconds to apply the zombie goop and can be easily interrupted if surrounded.
- Night Hunters can be killed but they require many hits from a very strong melee weapon. More likely is that they will swarm you, latch on for a bite, and keep latching on until you are dead. Takedown and Camouflage is a MUCH better use of your time, and saves you from breaking weapons or wasting throwables.
- Green spitters can dish it out but they cant take it. They also tend to have elevated positions when possible. As such its better to deal with them first, move to an elevated spot, and then slowly take out the other enemies.
- Since you lose a fair amount of XP on death, it may be better to stockpile several survivor relief boxes and turn them all in at once for massive Survival XP and multiple levels. Grabbing any loot and opening locks is much easier when camouflaged as opposed to trying to fight off hordes or distract them with thrown items.
- Live, healthy humans are surprisingly tough. They can block melee attacks and thrown weapons, they have the good sense to run from explosives, and it seems like they tend to take more direct hits than most infected. However, they are still subject to instant decapitation, they tend not to guard their legs very well during melee, they drop instantly when losing any limb, they take fewer bullets to die than zombies, and they also die quicker from flames whether it be molotov or nearby barrels. Even if alive, they don't fight back while aflame.
- The game-play changes significantly when you acquire the grappling hook at level 12 and its recommended you focus on Survivor XP until you get it.
Keep in mind some missions in the main quest will preclude you from using the hook for utterly asinine reasons, and you will have to climb the old fashioned way on occasion. It is however the preferred method for escaping zombie mobs if camouflage just isn't enough or cant be done.