GHOST 1.0

All the "Accumulate X energy cubes" achievements require that you attain that amount at one given moment. Meaning that for this achievement you need to have 5000 cubes on you to unlock it. Not much to say in regards to earning this one, you likely won't earn it until you get to around the green zone if you stockpile but I would highly suggest you don't worry about it until later, as the later enemies and alarm areas seem to drop more energy cubes as you get further in the game.

BE AWARE that if you die: YOU LOSE ALL YOUR CUBES!! You can always go back to a save spot and restore your health if you are in danger of dying and I would suggest doing so if you are ever doubtful of your survival