After beating the game go back to the omega system( talk to captain of the Elsa) and do what you did the first time, ther will be no bosses to stop you reaching him this time(i think you fight albido after I don't know he beat me the seond time I fought him)
When you fight marguls for the second time when he makes them shadows if youmattack them the real one loses hp and the fake gains hp attacking the shadows does more damage on the real one than attacking the real one. You can land 4645 damage in a one doubble attack on them causeing 4645 damage on the real one.
When you first take control of the robot guy in miltia (i forget his name) you have got to go meet your friends.
Go find them and then you get a couple of cutscenes where you get chased by e.s. Robots. Anyway carry on with your mission until you get to a cutscene where you see a helicopter that drops 4 p.s.s. Soldiers.
Defeat these guys and just keep waiting for the beam fence so you can get yet another battle. Keep doing this over and over until your on at least level 20 because you have a really tough boss battle to do later.