Dead Island

Game Cheats:
Free money hint:
After discovering the Church and the Warehouse and you are in the City, go to the Warehouse and get the Hammer and Baseball Bat. Then, fast travel to the Church and sell both items. When you travel back to the Warehouse, the items will have respawned. Repeat this as many times as you want.

Infinite Diamonds hint:
On Level 7, you can get a Diamond from the safe in the Mayor's office. If you go back into the sewers, but then turn round and check the safe again, the Diamond should have spawned back in there again. Sell the diamonds for tons of money.

Saving hint:
Dead Island annoyingly only saves at pre-determined points (though this arguably makes it more addictive). To get it to save whenever you want, go to the Controls menu and change the layout from Analog to Digital or Digital to Analog. This causes the game to autosave. You can then obviously change the controls back and carry on playing.

Logan duplication glitch:
As Logan, hold down the aim button (left trigger) and hold down the fury button while aiming at multiple zombies. Then, pull the right trigger. Instead of logan using his knives, he will be throwing your equipped weapon. Throwing the weapons will cause the game to duplicate your equipped item.

Item duplication hints:
-Note: This must be done in solo mode. When you reach a checkpoint during any campaign quest, drop the item on the ground you want to duplicate (if you want, all your items in your inventory). Then, kill yourself by using deobombs or molotovs, When the respawn timer starts counting down, pause the game and reload your checkpoint. When you respawn, all the weapons you dropped will be back in your inventory and also still be laying on the ground where you dropped them. You also do not suffer the cash penalty from dying since you reloaded the checkpoint.
-Note: This trick does not work with projectile weapons. Hold L1 then hold R1 + TRIANGLE. If done correctly, there should be two of the same weapon on the ground and it will show that you threw and dropped the same weapon. Repeat this as many times as desired. You can use this trick to make money in game or in online play, and you can supply teammates with strong weapons. You can also duplicate a weapon instead of repairing it. Note: This also works with modified and upgraded weapons.
"Oh, No You Don't" trophy hint:
Note: This can only be unlocked with Sam B after unlocking his Tackle ability. Play Chapter 16, "Locked Up". Once you reach the checkpoint where you have to "Find another way to the cell block control room", go around to get to the control room. When you open the door to the cell blocks, there is a stairway going down and there you will see the Ram. Let him follow you upstairs and go back in the hallway. Leave the door open. The Ram will try to ram you down, but he won't be able to get past the door. This is where you can weaken him until his life is close to dead. Then, deliver the final blows with you Tackle ability.

Chrome 2 easter egg:
In the hotel during the quest "BORN TO BE WILD," speak to Mike Davies. After that, move to the next room that has a workbench. Enter the next room to find one of the computers to reboot. If you look at the wall to the side of the desk with the fan on it, you will see a poster displaying "Chrome 2," one of Techland's next upcoming games.

Achievements:

10 heads are better than 1 (Bronze)
Objective: Kill 10 zombies in a row with headshots.

A taste of everything (Bronze)
Objective: Kill a zombie with 10 different melee weapons.

Ah! Spoiled meat! (Bronze)
Objective: Kill a Butcher using an axe.

Can't touch this (Bronze)
Objective: Use a hammer to kill a series of 15 zombies without taking damage.

Cardio (Bronze)
Objective: Travel a distance of 20 kilometers on foot.

Catch! (Bronze)
Objective: Kill an Infected with a grenade blast.

Dedicated student (Bronze)
Objective: Reach level 25.

First! (Bronze)
Objective: Kill a Suicider with a grenade.

Gesundheit! (Bronze)
Objective: Heal yourself with a medikit 100 times.

Going steady (Bronze)
Objective: Complete 25 quests while playing with at least one co-op partner.

Gotta find'em all (Bronze)
Objective: Find 60 collectibles.

Guns don't kill but they help (Bronze)
Objective: Kill 250 zombies using firearms.

Hack & slash (Bronze)
Objective: Kill 250 zombies using edged melee weapons.

Humanitarian (Bronze)
Objective: Kill 50 human enemies.

Karma-geddon (Bronze)
Objective: Kill 50 zombies using a vehicle.

Knock, knock (Bronze)
Objective: Breach a locked door with the first blow.

Learning the ropes (Bronze)
Objective: Reach level 10.

Light my fire (Bronze)
Objective: Set 10 zombies on fire simultaneously.

Ménage ŕ trois (Bronze)
Objective: Complete 5 quests with 3 co-op partners.

Nearly there (Bronze)
Objective: Find 120 collectibles.

Need a hand? (Bronze)
Objective: Join another player's game.

On, no you didn't (Bronze)
Objective: Kill a Ram using tackle skill.

One is all I need (Bronze)
Objective: Kill 5 Infected in a row with a single blow.

Originality (Bronze)
Objective: Play in a co-op team of 4 different playable characters.

People Person (Bronze)
Objective: Play with 10 different co-op partners for at least 15 minutes each.

Rageman (Bronze)
Objective: Kill 100 enemies with Fury attacks.

Road Trip (Bronze)
Objective: Drive a total distance of 10 kilometers.

Tae Kwon Leap (Bronze)
Objective: Kill 25 zombies with your bare fists.

Tis but a flesh wound! (Bronze)
Objective: Sever 100 limbs.

To put it bluntly (Bronze)
Objective: Kill 250 zombies using blunt melee weapons.

Together in the light (Bronze)
Objective: Complete 5 quests in a single co-op game with the game partners.

Warranty Void if Used (Bronze)
Objective: Create a customized weapon.

Busy, busy, busy (Silver)
Objective: Finish 75 quests cumulatively.

I want one of those (Silver)
Objective: Customize 25 weapons.

Right 4 Life (Silver)
Objective: Complete act I with 4 different characters.

School of hard knocks (Silver)
Objective: Reach level 50.

Steam Punk (Silver)
Objective: Create weapons to rival the gods of fire or thunder.

Swing them sticks (Silver)
Objective: Kill 150 enemies using Analog Fighting controls.

There and back again (Silver)
Objective: Explore the entire island.

Rootin' Tootin' Lootin' (Gold)
Objective: Loot 5 Exceptional Weapons.

The Whole World Went Away (Platinum)
Objective: Collect all other trophies.

Secret Trophies

A very special day (Bronze)
Objective: Kill 250 zombies with modified weapons.

Everybody lies (Bronze)
Objective: Use a large medkit to heal an injury of 5% or less.

How many days exactly? (Bronze)
Objective: Play Dead Island at least 28 days after starting it for the first time.

Savior (Bronze)
Objective: Save 5 people besieged by zombies.

Banoi Redemption (Silver)
Objective: Complete act IV.

Hell in paradise (Silver)
Objective: Complete act I.

King of the jungle (Silver)
Objective: Complete act III.

No raccoons in here (Silver)
Objective: Complete act II.

DLC: Bloodbath Arena

Complete a set (Bronze)
Objective: Kill enemies of 6 different types during a single round.

Fancy (Bronze)
Objective: Survive 10 consecutive waves using only custom weapons.

Gladiator school (Bronze)
Objective: Survive 15 consecutive waves with each of the 4 characters.

Looking for trouble (Bronze)
Objective: Survive 5 waves in each of the 4 Arenas.

Out of honey? Chew bees! (Bronze)
Objective: Survive 5 waves using only your fists and legs.

Stick it to the enemy (Bronze)
Objective: Survive 15 consecutive waves using the analog combat controls.

Wave and Smile (Bronze)
Objective: Survive a wave of enemies in any Arena.

Death Incarnate (Silver)
Objective: Survive wave 30.

Extreme Firefighting (Silver)
Objective: Set 5 enemies on fire and then kill them with explosives.

Morituri te salutant (Silver)
Objective: Survive 30 consecutive waves with at least one co-op player.