PROTOTYPE Cheats

Repossession (Bronze) - Seize 50 vehicles from enemy hands
Return Fire (Bronze) - Catch any object tossed by a hydra; and throw it back
Revenge Revisited (Gold) - Complete story mode on hard difficulty
Self-Deception (Bronze) - Discover what happened to Alex Mercer through the web of intrigue
SME (Bronze) - Gain the ability to drive and fly all vehicles
Speed Bumps (Bronze) - Run over 500 characters in a single tank
Streetwise (Silver) - Collect all landmark collectibles scattered across New York City
Surface-To-Air (Bronze) - Shoot down 50 helicopters while driving armor
The butcher (Silver) - Kill 50 characters in 5 seconds
The Cleaner (Silver) - Destroy 10 military bases or infected hives in New York City
The First Thread (Bronze) - Unlock the web of intrigue
Threat Elevated (Bronze) - Destroy 25 strike teams
Trail Of Corpses (Silver) - Kill 53,596 infected
Unnatural Selection (Silver) - Acquire all available upgrades
Web Of Knowledge (Gold) - Acquire all nodes of the web of intrigue
Wrecking Yard (Bronze) - Destroy 2,000 Vehicles

New Game+
Replay the story mode with all of the powers and upgrades already obtained.

Unlock Platinum/Radical Events
To unlock the extremely difficult Platinum events, earn Gold in every event. There are also Radical events which are nigh impossible.

Easy+ and Normal+
Mercer keeps all his ep, woi and abilities acquired when you start a new game+(easy and normal)

Easy+: Beat the game on easy or Normal
Normal+: Beat the game on Normal

Hard Mode
Beat the game in Normal mode to unlock it. This goes for all Prototype games on all systems.

Unlockable Secret Story event
Complete all Scientist Consume events to reveal Karen Parker's location after her disappearance.

Easy Thermobaric Tank
First you must unlock the Kill Event called "Rolling Thunder," which appears between the East Village and the Lower East Side (one block from the East coast). Right next to the Event is a Thermobaric Tank. Jumping into it will activate the Event, but you can back out of it before the Event begins. Do this correctly and you'll have a free tank. Note: If you exit the tank it or use it to destroy a Hive or Base it will vanish. You can grab it again at the Event point.

Easy "The Butcher" and "Speed Bumps" Achievements
To easily get "The Butcher" Achievement, which requires you to kill 50 people in five seconds (including pedestrians, military, infected etc.), wait until you have the ability to hijack a tank. Drive into a red zone that typically has a lot of fleeing normal and infected civilians and stick to driving on the side walk. Keep up with this same tactic to unlock Speed Bumps, which requires you to run over 500 people in a single tank.

Easy "Half-Truths" Achievement
An easy spot to complete "Half-Truths" is the mission in which you lead the Leader Hunter to Ragland. Complete your objectives unnoticed (shouldn't be a problem) until you are prompted to lure the Hunter. Look at the map and notice that it is mainly covered in red (infected zones) and two blue (military) zones, one on the far east and far west. There is an unclaimed area straight up the middle. Stick to this path and you won't alert the military as they have their hands full already.

Easy "The Cleaner" Achievement
"The Cleaner" Achievement requires you to destroy 10 military bases or infected hives. Choose Hives. Hives are being pummeled by the military by the time you get there, so some of the work is already done. All you have do is finish them off. Hijack a tank and destroy it. NOTE: The hives destroyed during missions count as well.

Easy "Misconception" Achievement and EP
The "Misconception" Achievement requires you to destroy 25 infected water towers before they hatch. Do this after you get your powers back -- when Ragland helps you -- as there seem to be more of them in abundance. Lock on to one and run up the corresponding building, jump to the roof and use the flying kick attack, causing more than half of the life bar to be depleted. Upon landing, follow up quickly with a combo. To make it a little faster, use the "claws" powers.

Later in the game this becomes even easier. Just hijack a helicopter, fly over infected areas and keep tapping the target button until you target a water tower (or helicopter or Hive) and fire away.

The "Friendly Fire" and "Projectiles" Kill Events as both have helicopters sitting next to the Event markers, so grab those and exit the event for a free 'copter.

Unlimited EP Exploit
On mission 22/31, where you get the first cell phone cut scene, you'll be asked to jack a Black ops helicopter. Once you have the helicopter, you are prompted to pick up a few Black Ops guys and then destroy a Hive. Do not destroy the Hive!

You now have a helicopter with unlimited missiles, no time limit, and as long as you don't destroy the Hive, you can blow up anything else without it kicking off the alert meter. This also allows you to get out of the helicopter without it ending the mission (useful for collecting Memory Strands).

The easiest way to get EP in this is to switch to your Infected Vision and fly around blowing up infected water towers. You can save your game in the middle of this mission if you need a break and do the same thing. You can max out your skills and then some using this exploit.

Collectible Vision
It's sometimes difficult to spot Landmark and Hint Collectibles. Switch on your Infected Vision (or Thermal Vision) to help discern them.

Mind the Crows
Infected water towers are always circled by squawking crows. This makes it easier to track them down

Smooth Landing Speed Boost
After jumping, avoid using both of your dashes while airborne and save one to use just before landing. If timed correctly, you should hit the ground at near full speed, which is very useful when attempting to evade the military or during a timed activity. Note: This doesn't work for the highest of drops.