To make this work you must first beat the game on New Game+ mode with the Military Suit purchased and equipped and have the game saved just before the last boss. When the game ends skip the credits and do not save when you are prompted but instead start a completely new game on 'Impossible' difficulty and you will begin the game wearing the Military Suit.
This feature is enabled if you save the game when you have completed it and then load the 'Cleared Game' save and start a new game. In New Game+ you will retain ALL your upgraded equipment from your original game along with 10 extra power nodes, 50,000 extra credits, and the schematic for the Military suit (a Level 6 suit that costs 99,000 credits).
If you're struggling with the game and could use some extra help then pause the game and enter the following codes to activate the corresponding effect. When a code has been entered in correctly and you have heard the confirmation sound press 'Start' to resume the game with the desired effect enabled (Some codes may only be enabled once per game).
Refill Stasis and Kinesis Energy: Pause gameplay and press X, Y(2), X, Y.
Refill Oxygen: Pause gameplay and press X(2), Y(3).
+2 Nodes: Pause gameplay and press Y, X(3), Y.
+1,000 Credits: Pause gameplay and press X(3), Y, X.
+2,000 Credits: Pause gameplay and press X(3), Y(2).
+5,000 Credits: Pause gameplay and press X(3), Y, X, Y.
+10,000 Credits: Pause gameplay and press X, Y(3), X(2), Y.