When your in a Master Node the place where you get to upgrade yourself, There's a battle right ?
If the enemy's are to hard go to the upgrade area. Shoot down at them with out taking any damage at all. And then while your up there use Time dilation attacks. Use the cheat codes for this game as needed for health and energy while your up there.

Press the following buttons after pausing: Up, Up, Down, Down, Left, Right, Left

Restore Life: L3 + right
Restore Time Dilation: L3 + up

-Restore Health-
Press
Up, Up, Down, Down, Left, Right, Left, Right, then L2 + Right during game play.

-Restore Time Dilation-
Press
Up, Up, Down, Down, Left, Right, Left, Right then L2 + Up during game play.