Killer is Dead Chosen by the Moon is the last episode in the videogame; therefore, it includes the final boss fight.
If you complete Episode 12, you will be able to unlock all corresponding Killer is Dead achievements, you will unlock a new difficulty mode, and you will be able to replay all previous missions in the game.
The action in Chosen by the Moon, takes place on the dark side of the moon, where Mondo visits his brother David.
Episode 12 is similar to Episode 4, meaning that you will have to explore Davids mansion again, but this time the path you will follow is reversed.
At the end of the episode, you have to beat David again; however, only the first phase of the boss battle is similar to the one you have completed in Episode 4.
Client: Mondo Zappa
After the introductory cutscene, you arrive at Davids mansion, and in the lobby you will be ambushed by a large number of Wires. Clean the ground floor and smash all green pots to replenish your blood and health. Follow the door to the right, and in the next room continue to smash the pots.
Destroy the Wires that come inside through the windows, and then approach the painting showing David and jump through it. As you enter the room with two pool tables, take out all enemies, but stay away from the dark matter (purple mist).
Go through the next door (you have only one path to follow at this point), and then through the next one. Follow the stairs down and shoot the green pot to discover a secret panel. Activate it and follow the door on the left side, to reach a hidden chamber with more green pots.
Destroy them, and then retrace your steps back to the panel. On the right side of the mirror, you can see some crates, and if you smash them you will find a secret wall that can be destroyed to enter another secret chamber (one of Scarletts locations in Episode 4).
Destroy more pots for blood and health, and then jump through the mirror near the green panel.
Continue to fight your way through the mansion, and make sure you kill all Wires you encounter. Eventually, the path will take you back to the lobby.
Once you clear the area, stop in front of Davids painting that turns into a mirror, and purchase as many upgrades as you can. Once you jump through the mirror, you will start the final boss fight and there is no turning back.
David Boss Fight
The second time you fight David, you will notice that he became more powerful than he was before; however, just like the first time, the battle features three phases. The first phase starts after the dialogue between the two brothers, and it is similar to the one you have experienced in Episode 4.
You have to focus on depleting Davids health bar, and then you have to constantly mash the attack button to push back his sword. Perform a finishing move after David falls to the ground, and you will start the second phase. For the second phase, David will turn into a demon.
This phase is focused on melee combat and dodging. Try to dodge left or right when you see him rushing towards you, or raising his sword.
From time to time, you will see David creating a series of purple spheres that follow you. To interrupt him, shoot his belt or hit it with your sword, then continue to dodge around and strike the boss.
The third phase of the boss battle is even harder than the second one, because it is focused on dodging. David is faster than Mondo, and if he catches you he will hit you continuously, stunning Mondo for a short period of time. As you will notice, during the final phase David assumes his human form.
To beat him, you have to rely on Mondos blocking speed and on his Adrenaline Burst. Dodge all the time and dont try to shoot David because he will catch you. If you continue to dodge, you will eventually trigger the Adrenaline Burst move and you will be able to hit him.
Repeat the same step until David is down on his knees, and then execute him. Watch the final cutscene and the credits to unlock the Very Hard Mode and all episodes featured in Killer is Dead.