Feel free to comment with any info you find and I'll try to keep this updated.
Generators
There are 6 generators in the game. If you succesfully turn them on you get your points back. You must stay in the area but do NOT need to kill the special zombies that spawn (they don't give a lot of points). Costs to start the generator shown below:
1 Player - 200
2 Players - 400
3 Players - 600
4 Players - 800
(thanks to Niek12)
Musical Parts
Part 1
-- The Grammophone is found in the excavation site, it'll be on the floor when you go down the stairs. Place Gramophone in staircase of excavation site. Remember to always take your gramophone back when you are done.
Part 2
-- On a ledge in a trench near the blocked door to the church
-- In the top area of the excavation site
-- Upon entering No Mans Land, turn left towards Generator Station 4. Right behind the first Excavation Site sign by the small motor/generator.
Staff Parts (Records and components)
Part 1 (Red)
-- (Record) On a crate on the left side of Generator 6
-- Obtained from killing the robot zombies w/ claws (Panzer). Doesn't always drop the first time.
-- Shoot down the glowing red plane (after level 12) and it will drop a part which you need to pick up
-- Turn on the 6th generator (others don't have to be on) and hit the box at Generator 6
-- Another possible location for one of these is on the bench underneath the church
Part 2 (Yellow)
-- (Record) By Generator Station 5 on a ledge
-- Each of the 3 parts are in In one of the giant robots (How to get in giant robot)
Part 3 (Purple)
-- (Record) By Generator Station 4 on a table or ledge OR in the cart in the muddy area near Generator Station 4 OR in the bottom of the wind tunnel by Generator Station 4.
-- You need to ride the tank which is under the church to get the 3 purple parts, then you'll see a area you can jump on to get the first part (Its on the right side.) then after the tank takes a break halfway through the route and you continue to ride it there will be a part on the left and the last one will be on the right again. (Have to jump to both of them like the first part.)
Part 4 (Blue)
-- (Record) In the shelter next to Generator Shelter 2 on a shelf
-- All of the blue parts have to be dug up, they spawn randomly as far as I know (possibly when it is snowing versus any other time)
(thanks to Niek12 and Ninjambie for most of the music/staff part info)
Apparently there are also Upgraded staffs/staves. The upgraded staves are stronger, have more ammo, and can charge up to create a larger blast. The names of these staves are as follows:
Fire Staff -- Kagutsuchi's Blood
Ice Staff -- ULL's Arrow (also with an attachment called Sekhmet's Vigor to revive other players like ballistic knives)
Wind Staff -- Boreal's Fury
Lightning Staff -- Kimat's Bite
*Note - The upgraded staves all have the revive players attachment
Maxis Drone
Part 1
-- In the tunnel behind the Church behind where the tank first spawns
Part 2
-- In Labratory (starting room) - always in this location
Part 3
-- In the Excavation Site by the 4 statues where you build the staffs (thanks to Niek12)
Zombie Shield
Part 1 (any of the locations below)
-- By the "Fire" - Outside the first door to Generator Station 3 take an immediate left. Part is at the very end on a table.
-- Out first door to Generator Station 3 by the wheelbarrow in the tunnel straight ahead
-- By a box below in the trench by Generator Station 3
Part 2 (any of the locations below)
-- Upon entering the No Mans Land area, go just to the right of the MP40 into the mud area where the robots step. It should be in a corner to the right.
-- Against the back wall in the muddy area behind Juggernog
Part 3 (any of the locations below)
-- By the wheelbarrow out the door to Generator 2 in the first tunnel
-- In wheelbarrow (w/ Zombie in it) past Generator 2 and past the No Mans Land door at the dead end
-- On top of the shelter by Generator 2
Locations of Staff Tunnels aka Crazy Places (used to get the crystals for the staff)
You need to build the Grammophone first and then place it on the table in these tunnels in order to open up the portal. This allows you to go in and grab the crystals for the staff you are building. Be sure to grab the Grammophone when you leave the tunnel. To build them you go to the bottom of the Excavation Site.
Fire (Red) - Directly outside the first door of the Labratory on the way to Generator 3. Make a U-Turn to the left once you go out the door.
Ice/Frost (Blue) - Under the church near Generator Station 6
Wind (Yellow) - Near Generator Station 4/Juggernog
Lightning (Purple) - Near Generator Station 5 (turn left when entering No Mans Land)
Staff Effects (all have an area effect)
Fire - Torches the zombies (Video)
Ice - Freezes the zombies temporarily slowing them and then killing them (Video)
Wind - Extreme burst of wind launching and killing the zombies (Video)
Lightning - Electrocutes the zombies with bursts of electricity (Video)
Guns
B235 (1000) - Outside the Labratory towards Generator Station 3 (stay left)
B235 (1000) - Underneth the church in the ice tunnel
Remington 870 MCS (900) - Outside the Labratory towards Generator Station 2 take the first left
Remington 870 MCS (900) - In the "Lightning" tunnel in No Mans Land by Generator Station 5. On the first landing.
Remington 870 MCS (900) - Behind Generator Station 6
AK74U (1200) - Below Generator Station 3 by the steps
AK74U (1200) - In the Excavation Site
MP40 (1200) - Straight out of the No Mans Land Exit near the Excavation Center
MP40 (1200) - In the mud pit behind Juggernog
MP40 (1200) - In the bunker next to Generator Station 2
Balista (500) - Starting Building by door to Station Generator 2
M14 (500) - Starting Room
STG44 (1400) - At the top of the church
STG44 (1400) - Under the Excavation Site
Others?
Equipment / Grenades
Claymores (1000) - Outside the Labratory towards Generator Station 2 in the first tunnel
Claymores (1000) - By Generator Station 5
Semtex (250) - Heading towards Generator Station 3 take the last left before going into the Generator Station 3 door
Semtex (250) - Bottom of the church by the front of the tank.
Perks
Quick Revive (500) - In Starting Building by Generator 1
Speed Cola (3000) - In the mud by Generator 3
Stamin-Up (2000) - By Generator 5
Juggernaug (2500) - By Generator 4
Mule Kick (4000) - In Excavation Site Tunnel
Others?
Pack-A-Punch
Located at the top of the Excavation Site. All 6 Generators must be turned on.
Shovels
By the M14 in the inital spawn in the Labratory
By first door to Generator Station 3 in starting building
"Wind" Ramp next to Generator Station 4 in No Mans Land going underground. At the bottom of the first landing to the left of the Buildable Table
The forth shovel is some where next to the tank spawn
After you dig up enough items (anywhere from 30-75) your shovel will turn Gold. It only lasts for that game and is also per person, not as a team. From that point on, the items you dig up are more likely to be rare or better. When combined w/ Zombie Blood you may be able to see some "red" dig sites that provide perks. If you continue to dig you may get a Golden Helmet. This protects you from being crushed by the robots (either foot).
Musical Easter Egg #1
This will play "Archangel" featuring Eliena Seigman. Hold in X (or PS Equivelent) next to the Green Glowing Rocks to activate the item. No prompt will show up but you will hear a confirmation sound.
Green glowing rock by the first door to Generator Station 3 in starting building
Green glowing rock under the shelves in No Mans Land building on the top level by the exit door
Green glowing rock by the Excavation Site when you walk up it and go left just before the part you can jump down (thanks to PFISH1). You may need to lay down to activate it. The 3rd part may not activate till at least round 6.
Musical Easter Egg #2
This will play "Shepherd of Fire" by Avenged Sevenfold. It is achieved by activating three red dialed radios (as opposed to the normal white ones). Hold in X (or PS Equivelent) to activate it. No prompt will show up but you will hear a confirmation sound.
Radio 1 - In the Excavation Site on the scaffolding
Radio 2 - In the "Crazy Place", where you go to get the crystals for the staffs, on the edge near fire.
Radio 3 - In the robot that walks over the church
Buildable Stations
Bottom level of No Mans Land building
"Wind" Ramp next to Generator 4 in No Mans Land going underground. At the bottom of the first landing is the Table
Underneath the church
Others?
Chest Locations (to fill Zombie souls)
-- After entering No Mans Land, turn left. Go past the Excavation site. The area at the bottom of the ramp has the chest.
-- Next to Generator 5
-- Just after the opening to the path to the church
-- Behind Juggernog
Air Strike Grenades (similar to Monkeys) - Video
-- tablets found on table in back of tank station (next to generator 2 near the mud)
-- tablets must be cleansed in church holy water with zombie souls (using only thunder fists)
-- tablets must be returned to tank station (without getting dirty {holder stepping in mud})
-- souls must be fed to tablets (only using thunder fists)
Myster Box Confirmed Items (initial list from timelordalex in another thread)
Monkeys
MG08
M1927
KSG
M1216
Skorpion Evo
Scar-H
Hamr
Galil
Five Sevens
Python
AK74u (with attachments such as extended clip)
B23R (with attachments such as extended clip)
MP40 (with attachments such as extended clip)
STG (with attachments such as extended clip)
War Machine (of course, how could it not return)
DSR