Bosses in this game can be a pain so here's some tips for some of them.
Jov Leonov. Use the cheat to unlock all powers and when he comes down the lift after you have destroyed all of the machines use PK on him three times to kill him.
Edgar Barret. Use the cheat to unlock any one of all the Edgar Barret skins to gain the ability to lift, block, throw and stop all the train carriages and heavy objects in the battle area. The General's skin also works.
Wei Lui. Use PK on the stone samurai's to stop their movement for a few seconds before you mind drain them. When she transforms use the infinite ammo cheat to be able to destroy her three heads quickly with an automatic weapon, to stop her attacking for a while use PK on her for a while to make her rampage across the room.
Nicholas Wrightson. Use the infinite ammo cheat and equip an automatic weapon. Once you have done this hide behind the box at the entrance and don't stop shooting at his computer screens.
The General. Use the infinite ammo cheat so that your new power will never run out during the fight. This way you only have to destroy one structure and you only have to find one sphere of power. When he uses his third attack he will dissapear and reappear later on with a quick almost unavoidable blast attack.
To avoid it use aura view when he dissapears and attack him, for some reason he won't use his blast attack afterwards. To avoid his other two attacks hide under one of the little bridges and leave to attack him between each one. With these tips you can finish the battle on full health.
Added by: tomsmiley18 Sep 2nd 2006, ID#23123