Gol Acheron is the final boss in Jak and Daxter: The Precursor Legacy VII, fought on top of The Dark Eco Silos. Although defeating him will end the game, it can continue until you have every single Power Cell. Nevertheless, this is the final encounter and it will not be an easy task in the least. Gol Acheron fights from within a massive Precursor Robot similarly to the ending of the real Jak and Daxter, constructed from Precursor Artifacts and Lurker creations. There are two distinct phases that it shifts between, depending on the damage it takes.
This boss can only truly be damaged in Offense Phase, but in order to shift it into that phase, Jak and Daxter will have to needle this guy with attacks whenever possible. In Defense Phase, it hovers a distance from the silo, and attacks with long-range things. It can fire a cannon from its foot which shoots a straight blue beam in your direction. Spring out of the way to dodge it easily, but be sure to not spring off the edge of the silo! It can also throw a huge iron boomerang from its backside. Although you can dodge this as it comes your way, be sure to dodge again when it swings back towards the boss (after this boss starts taking damage in Offense Phase, it will use two of these boomerangs at once in the Defense Phase.) When the boss prepares its big bomb laser, the massive energy it stores will open a Blue Eco vent for a short time. Use it to ride the launcher up into the air to avoid the incoming mass explosion! Whenever possible, pick up the Yellow Eco charges floating around and shoot the robot's foot cannon whenever you have a chance. After enough of these attacks on the foot cannon, the robot will shift into Offense Phase for about two minutes.
Now the robot will get mad, and it uses two distinct attacks. It will either fire several powerful blasts of white light from both of its hands, or it will focus all of its energy to a single beam of dark light. Both of these attacks do an insane amount of damage and are difficult to dodge, but after enough energy from these attacks builds up on the silo, the Blue Eco vent will open once more, allowing you to use the launcher to jump up to the robot's head. Use this time to damage it as much as you can, but be sure to jump back to the silo before the robot attempts to throw you off, potentially off the edge of the silo. Once two minutes are up, it will back off and revert to its Defense Phase moves. After enough attacks on the head during Offense Phase, the robot will back off, smoking in fury.
From the four towers nearby, beams of different colored eco- green, blue, red, and yellow- form together overhead to create White Eco, previously thought to be just a legend. Now, the robot prepares a ton of explosives to finish Jak and Daxter both off, once and for all. There is very little time left before the robot strikes, and a countdown begins from ten. You have to think fast. Grab the Blue Eco from the vent and position yourself on the launcher- then blast through the White Eco charge created by the beams, aiming in the direction of the robot. Use the attack button.
The robot will be completely demolished through the combination of an incredible White Eco charge and its own explosive weaponry. The last piece of the robot with Gol Acheron inside, the head, falls into the Dark Eco Silo and is shut inside. Finally, it's over.