1 mars. Shoot at a distance and dodge his charges.
2 Lycaon. Same as mars but more dodging or his swords will heat up your weapons
3 Minos. Use the center pillar to shield against the fire moves and attack after that.
4 Braireus. Use the Emcon to make him fall and use tri lasers to hit him.
5 sphinx. Use tri lasers at distance and use cover and run from his attacks.
6 Alcmaeon. Your only defence are moving pillars that are not that good for 2 of his attacks encircle you and them and they wont help when he uses a pulse cannon that is why you move to the farthest edge.
7 Statius. I've just beat him today cause theres almost no defence and he can teleport to you but if you dodge like crazy after you use the Emcon the instant he teleports to you or he will wont fall and he'll use a barrage of a combo on you. There is still 1 boss left but I have not made it to him yet.

In the begining of the game go to the first floor where you get your first weapons. Collect the weapons and go to the terminal and press X. Go to equip and choose any slot. Instead of equiping the weapons press triangle and turn the weapons into elixer. Exit the terminal and the weapons will be back on the ground but you will still have the elixer. Do this as many times as you need to make your character stronger than anything in the game.