Generators are used to light up specific areas (not so useful in daytime but the sound of the generator can be a great distraction).
Windows and doors can be destroyed using melee attacks. The axes and sledgehammers you can pick up will destroy doors in one hit, even barricaded ones.
Speaking of doors, shooting a door can cause it to swing open. On top of this, if you sprint at a door with a charged melee, you will open it much faster and are able to essentially run into a room without waiting for it to fully open.
Doors with a plank near them can be barricaded.
Doors open quieter if you open them whilst crouching.
Any lanterns on the map that you can turn on and off (not ones you can pick up) can be shot and will explode, having the same effect a firebomb does. This works really well with lanterns that are suspended, as they will fall and damage anyone underneath.
If you melee an armored zombie in the legs, it will break their leg armor off, causing them to charge at you much slower.
Red barrels explode when shot, and yellow barrels burst on fire when shot.
Flares can be put out by being melee’d or shot.
The dogs inside the kennels can be shot and killed, but not melee’d.
You can climb inside chicken kennels!
Firebombs will kill crows (Still makes noise but interesting).
Crouching through any hanging chains or broken glass/cans will produce little to no noise.
At a resupply point, nobody can take ammo from a box that has already been opened.
You can catch a downed player on fire to prevent them from being revived.
There is a small amount of bullet penetration in the game, meaning you can shoot enemies through wood and sheet metal.
When hives are killed their locusts will die as well.
You can use first aid kits to heal your partner.
Text chat can be seen by enemy players if they are close, similar to how you can hear players using voice chat if you are a short distance from them.