Jak II Cheats

On the menu screen

Begin by taking out your blaster and kill all the enemies. Then, shoot him repeatedly until more Metal Heads appear. Repeat this as many times as needed until he gets in the red. When he gets in the red, he will jump off the string things and will be on the ground. Avoid him until he shoots three lasers at you. He should now be on the other side of you. Take out the Peace Maker and shoot him. Repeat this as many times needed to defeat the Metal Head leader and complete the game.
When the battle starts, take out your Vulcan gun and fire at the Leader until he charges a shot. Get out of the way. Switch to your Blaster and run around the area, firing at the Leader occasionally. Take out the bugs if they get too close; otherwise stay away from them. When you get to phase two (one third of his health is gone), continue firing at him until the flying Metal Heads approach you. If you have enough Eco, turn into Dark Jak. Take some of the lesser enemies then do a Dark Blast close to the Leader (takes about half a health bar). Repeat the earlier process until the Leader starts running around. Continue running until his blasts are coming from the side instead of behind. Turn and blast him. Repeat to win.

Take or get a zoomer fly head on to a gaurd jump off before you hit him and he will fall over. he won't get ticked off at you and kill or hurt you so take all you anger out on thoughs red robo nerds.

To unlock an extra option on the Secrets Menu, collect the required number of Precursor Orbs. Here is a list of the extra options, along with the number of Orbs required to unlock each one:

5 - Toggle Jak's Goatee
15 - Mirror World
30 - Big Head Mode
45 - Small Head Mode
55 - Scrap Book 1
65 - Scene Player Act 1
75 - Vulcan Fury Course
85 - Scrap Book 2
95 - Scene Player Act 2
105 - Peace Maker Gun Course
115 - Scrap Book 3
125 - Scene Player Act 3
135 - Reverse Races
145 - Level Select
155 - Unlimited Ammo
165 - Unlimited Dark Jak
175 - Invulnerability
200 - Hero Mode

When you are fighting the Metal Head leader and you run out of ammo, break the boxes to get more for the blaster, but if you die just restart the game, you will not have lost anything and you will have as much ammo as you did when you started.