Dead Space Cheats

Exterminator (Bronze): Kill the Leviathan
Freeze (Bronze): Use Stasis on 50 Enemies
Full Arsenal (Silver): Own every Weapon in the game
Full Contact (Bronze): Kill 30 enemies with the Contact Beam
Get off my ship! (Bronze): Kill the Slug Boss
Greenhouse Effect (Bronze): Complete Chapter 6 on any difficulty setting
Keeper of the Faith (Bronze): Complete Chapter 10 on any difficulty setting
Kickin it (Bronze): Escape from a Lurker's grab attack 10 times
Lab Rat (Bronze): Complete Chapter 2 on any difficulty setting
Legend Teller (Silver): Collect 150 Logs
Live With The Hot Ones (Bronze): Kill 30 enemies with the Flamethrower
Marksman (Bronze): Dismember 20 Limbs
Maxed Out (Gold): Upgrade all weapons and equipment
Merchant (Bronze): Collect 8 schematics
Mindless Prey (Bronze): Kill the Hive Mind
One Gun (Gold): Beat the game using only the Plasma Cutter
Pack Rat (Bronze): Store 25 Items in Safe
Playing Catch (Bronze): Catch a Brute or Leviathan Pod using Kinesis
Pusher (Bronze): Kill 30 enemies with the Force Gun
Ragdoll Check (Bronze): Force an enemy into a Gravity Panel 5 times
S.O.S. (Bronze): Complete Chapter 7 on any difficulty setting
Slugger (Bronze): Kill the Slug Boss with more than 50% Shield strength remaining
Story Teller (Bronze): Collect 75 Logs
Strange Transmissions (Bronze): Complete Chapter 8 on any difficulty setting
Surgeon (Bronze): Dismember 500 Limbs
Survivor (Silver): Complete the game on any difficulty setting
There's Always Peng (Bronze): Find the Peng Treasure
Tool Time (Bronze): Kill 30 enemies with the Plasma Cutter
True Believer (Bronze): Complete Chapter 5 on any difficulty setting
Wreckage (Bronze): Complete Chapter 9 on any difficulty setting
Z-Baller (Bronze): Complete Level 6 in Zero-G Basketball

Impossible mode
Impossible mode: Complete the game on any difficulty setting.

Find the Peng and a note on Impossible mode
Peng is a treasure found in the Hangar in between the two sidewalks. As you leave the Kellion for the first time, look over the railing to your LEFT. There is a small statue lying on the ground. You need KINESIS to get it, so you can't grab it until Chapter 11. IMPOSSIBLE MODE Beat the game on any difficulty, save your game, and start a new game. Choose IMPOSSIBLE MODE, then play until you save your game at a kiosk (in a new slot if you like). The important thing to note is that impossible mode will not remain unlocked if you do not save a game that is playing in impossible mode.

10 power nodes: Beat the game on any difficulty level
50,000 credits: Beat the game on any difficulty level
Backstory logs: Beat the game on any difficulty level
Military suit: Beat the game on any difficulty level

New Game Plus
Save after finishing the game. Then, load your CLEARED GAME save. You will start a new game on the difficulty which you previously beat the game with all you Items, all your upgraded equipment, including 10 extra power nodes, 50,000 extra credits, and the schematic for the Military suit (a LEVEL 6 SUIT that costs 99,000 credits).