Scars Above

The Construct is a large, spider-like creature that attacks you in an arena where the floor is covered by ice. However, with the right tools the Construct is a pretty easy fight.

When the fight begins, the Construct will throw a few attacks at you, namely a charge attack and a ranged attack. While the Construct is on the ice surface of the arena, used charged fire gun attacks on its legs. Two charged shots will cause the targeted leg to heat up and melt through the ice. Repeat this process until three of it's legs have broken through the ice and then use your electric gun to shoot the exposed power coils that pop out once it's incapacitated. After hitting each core section twice, the Construct will reset and all you have to do is repeat the process of heating up three of it's legs and then shooting its power coils.

The Construct is the boss of Chapter 3--but to clarify, you will fight it TWICE during the chapter (once about 3/4 of the way through and the second time at the very end) and this achievement won't pop until after the second fight. I had panicked at first when it didn't pop after fighting it the first time. The first time it will flee at 25% health, but the second time you will be able to end it for good.

The easiest way to kill it during the first fight is to use the Thermic Charger (flame weapon) on the ice beneath the boss's legs while it's on the ice, breaking the ice and causing the leg to slip into freezing water and get stuck--this will take two shots in the same spot to break the ice. Do this to three legs and the boss will temporarily fall down into the water, applying the wet status to it (which increases damage taken from VERA), but more importantly will expose its weak spot: 3-4 electrified nodes sticking out of the left and right sides of it's face area. You will be able to get some more shots in after destroying those nodes before the boss gets back up, after which you can rinse and repeat until it flees at ~25% health. Keep in mind that during the first phase you will be accumulating hypothermia, so be sure to periodically use the Thermic Charger on the flame plants to clear that status.

The second fight is almost exactly the same until the boss reaches about 50%, though this time you won't have to worry about hypothermia. At 50% health, the boss will avoid the ice and instead begin to jump onto platforms on the outer edges of the room which will have 2-3 blue orbs appear on the left and right sides (these will be below where the boss is "perched" and it will continue to attack you at range from this spot). Shoot at these blue orbs/circles with VERA (one shot each) and if you're quick enough, it will do acid/corrosive damage to the boss and send it crashing to the ground, exposing weak points in a similar yet smaller area to the weak points in the first phase. Shoot them with VERA until the boss gets back up and starts jumping onto the platforms again. If you're not quick enough to shoot the orbs, the boss will jump to another platform (while launching attacks at you) and you'll have to try to quickly shoot the blue orbs again on the new platform while the boss is still on it. Just rinse and repeat this strategy, shooting the weak spots each time the boss falls down, and you should be able to defeat it for good within 1-3 cycles of the boss falling down, depending on the difficulty you're playing on.

When the boss falls and dies, the achievement should pop very soon after, and this will be the end of Chapter 3.