Dead Space Hints

First, you must beat the game on New Game Plus mode, with the Military Suit bought and equipped, and save the game right before the last boss. After the game ends and the credits roll, skip them, and do not save the game when it asks you to. Instead, immediately start a completely new game on Impossible difficulty, and you will start the game wearing the Military Suit.

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).