Destroy the plasma cannon turrets is a mission in Up Your Arsenal, taking place in the Korgon Base, Tyhrranosis. After destroying the power generators for the mortar launchers, Sasha Phyronix was able to send the dropship with the turboslider and Skrunch to Ratchet and Clank to destroy the four plasma cannon turrets before they could defeat the Momma Tyhrranoid.
For this mission, you will be using the turboslider to travel to the different plasma cannon turrets and destroy their respective power generator. The four turrets are contained in each of the four different corners of the map, marked as green on the minimap. For the most part, you will be required to park the turboslider somewhere before traveling on foot to destroy the power generator, after which you should return to where you parked the turboslider before proceeding. In between the turrets are several watchtowers with three-eyed tyhrranoids perched on top, which Skrunch will destroy with the turret. You can destroy the turrets in any order.
Drive to the top-right section of the map and park the turboslider roughly next to the puddle of water, in front of an elevated plateau. Jump onto the plateau to encounter a group of one-eyed tyhrranoids, ultra mecha-tyhrranoids, and three-eyed tyhrranoids. A good idea is to clear them out with the Nitro Launcher or Agents of Doom, or to use the Suck Cannon to suck up the one-eyed tyhrranoids and fire them against the ultra mecha-tyhrranoid. As you progress forward, a few three-eyed tyhrranoids are perched on top of plateaus; for these, use long-range weapons such as the N60 Storm. Clear out the enemies, and then use the wall-jump upwards to climb to the top of the first structure.
As you arrive, a dropship will drop several three-eyed tyhrranoids. You likely don't have the firepower to destroy it yet, so simply defeat the tyhrranoids and head across the base left, where more will appear. A good idea is to use the Miniturret Glove to slow their advance towards you as you fire any long-range weapon against them until it is safe to cross the bridge. As you do, a dropship will drop more tyhrranoids, so just destroy them and keep going. Turn left and jump up a set of platforms to find the power generator. The power generator is the main target here, so simply destroy it and it will kill all nearby enemies.
This is the easiest turret by far, and can be destroyed without even leaving the turboslider. Simply take the bridge on the southeast end of the map, and keep driving the turboslider in across the bridge and inside the structure on the island. Ram the turboslider into the power generator to destroy it.
Drive to the bottom-left area of the map and park the turboslider next to a series of plateaus. Jump out and climb the first few plateaus to find a set of ultra-mecha tyhrranoids clustered together, best destroyed with area-of-effect weapons such as the Nitro Launcher, Agents of Doom, or Plasma Whip. Hop across to the next plateau where three-eyed tyhrranoids are fought, dispatched easily through similar means. Past this, one-eyed tyhrranoids and ultra mecha-tyhrranoids guard the power generator inside the small cave. Using the Miniturret Glove to clear them out and make a safe path to the power generator can be helpful, as destroying the target will kill all nearby enemies.
This is the most complicated turret to destroy. Head to the western end of the map to find a plateau with a Gadgetron vendor on top of it and the entrance to a cave, which will take you down below to where you have to fight two ultra mecha-tyhrranoids. Climb a few of the plateaus, where you will encounter more tyhrranoid mechs, one-eyed, and three-eyed tyhrranoids, best cleared out with weapons that can deal with multiple targets, such as the Miniturret Glove, Plasma Whip, or Spitting Hydra. Eventually, you will come across a fork. The path left is inaccessible until you have the Hypershot, while the path right hopping across plateaus will lead to the turret.
As you jump between the plateaus on the right, proceed carefully, defeating the tyhrranoid saucers, mechs, and three-eyed tyhrranoids with long-range weapons, before jumping across as they could knock you off balance. Eventually, there will be a gap before you reach the exit to the tunnel. Consider using the Miniturret Glove and throwing down miniturrets, or firing with the Flux Rifle, from this vantage point, before you head down to encounter the last set of enemies. Head forward, and wall jump up to the top of the tower and destroy the power generator.
Once all turrets are destroyed, a cutscene commences, and you are taken to the front of the Momma Tyhrranoid's lair where the last mission, "Destroy the Momma Tyhrranoid", takes place.