How to Defeat the Final Boss in The Callisto Protocol on Maximum Security Difficulty - Prima Games

How to Defeat the Final Boss in The Callisto Protocol on Maximum Security Difficulty

A foolproof guide to defeating Alpha in The Callisto Protocol

by Grant Testa

One of the most challenging moments in The Callisto Protocol is the final boss fight against Alpha, requiring all of your grit, determination, everything you have learned throughout your travails in Black Iron Prison. This guide will provide everything you need to know to defeat Alpha and finish the campaign of The Callisto Protocol, including the best loadout and strategy for taking down the game’s final boss, even on the highest “Maximum Security” difficulty setting. Warning: major spoilers ahead.


Before you start this fight, while you can choose a loadout with weapons that best suit your playstyle and preferences, I would highly suggest using this arsenal against Alpha.

  • Riot Gun & as much ammo as possible
  • Assault Rifle & plentiful ammo
  • Hand Cannon & plentiful ammo
  • 3x Health Injector

Related: All Weapon Locations in The Callisto Protocol

The Callisto Protocol – Alpha Boss Fight Phase One

In the first phase, you fight the heavily mutated Captain Leon Ferris, who is now referred to as “Alpha,” in an encore of your previous duel from Chapter 7. The boss battle takes place in a room with two sections, a large interior circle we’ll call “the arena” and an outer section behind pillars that we will denote as “the ring” from now on. The entirety of Phase One takes place in the arena.

The fight starts with Alpha standing across from Jacob Lee, preparing to charge. Don’t shoot at Alpha, as it is a waste of ammunition. Instead wait for him to charge.

Alpha will kick things off by charging and throwing anywhere between three to seven punches in a furious tirade. Taking two or three of these strikes will lead to death, and there is no time to heal during Phase One. Simply avoid Alpha’s punches by alternating dodging left and right (it doesn’t matter which side you start, just stay consistent in alternation), and include an extra dodge for good measure.

Once Alpha has finished his assault, it is Jacob’s chance to strike back. Use the stun baton to unleash a counteroffensive on Alpha with your own combo of baton strikes.

After your own flurry of attacks, Jacob will also have an opportunity to take a counterattack gunshot against Alpha. Just make sure you are quick because Alpha will be coming back for another round of attacks very quickly. The Riot Gun or Hand Cannon are suggested for this phase.

Repeat the process of dodging and counterattacking, and you will quickly make it to the second phase of the final boss fight.

Related: Essential Tips in The Callisto Protocol That the Game Doesn’t Tell You

Phase Two: The Final Form of Alpha in The Callisto Protocol

In the second phase of The Callisto Protocol’s final boss fight, after a cutscene, Alpha will morph into a hulking alien monster, with a biological shield covering its face, as seen in the picture below.

Alpha has only two attacks, which are as follows:

Attack One: Alpha will attempt to strike Jacob with a swipe attack. If an attack lands, it is an instant, brutal kill, restarting Stage Two.

Attack Two: Alpha will throw projectiles at Jacob across the room. Even on Maximum Security difficulty, these projectiles don’t do a ton of damage, but can be deadly if Jacob is at low health.

Strategy: The easiest way to defeat Alpha is to remain in close proximity to the boss throughout most of Phase 2 within the inner arena section where the boss fight takes place. This causes Alpha to only throw easy-to-dodge swipes instead of projectiles. Keep evading Alpha’s attacks in either direction, while following up the dodges with a Riot Gun blast to the monster’s head. Eventually, the biological shield will dissipate.

After doing enough damage, Alpha will become staggered for a moment, and let out a roar/screech. It is imperative that you run to the outer ring section, and take cover behind pillars, as more enemies are going to enter into the fray. You can find these pillars as they have a lit blue panel near them. Switch weapons to the Assault Rifle or Hand Cannon.

During this part of Phase Two, four combustors (enemies that explode upon contact with Jacob) will start spawning from the outside ring walls, and working their way towards you from all directions. They must be quickly taken out from a safe distance, otherwise they can become overwhelming, and quickly decimate your health.

Combustors can be destroyed with one shot from any weapon, or through being thrown with the GRP (although this is sometimes too time consuming when compared to using firearms). Keep an eye on your surroundings, methodically take out the combustors, and don’t forget to look out for Alpha to make sure that he is not closing in on Jacob.

Healing during the Alpha Boss Fight in The Callisto Protocol

Once you have killed the four combustors, the one on one fight with Alpha’s final form will continue. If you are low on health, you can heal yourself with a health injector by doing the following:

  1. Give yourself a lot of space from Alpha.
  2. Wait for Alpha to throw projectiles, and evade them by strafing as he starts his throwing motion.
  3. While facing Alpha’s direction, start using a health injector, while simultaneously holding dodge in either direction.

Through this process you will be able to partially heal and prevent Alpha from instantly killing you.

Alpha’s head will once again be shrouded in the protective biological shield, which leads to repeating the process of Stage Two. To reiterate:

  1. Switch back to the Riot Gun,
  2. Dodge Alpha’s attacks and blast away.
  3. When Alpha is staggered and roars, run to the outer ring,
  4. Switch weapons to the Assault Rifle or Hand Cannon.
  5. Take out the four combustors, while keeping an eye out for where Alpha is.
  6. Go back into the inner arena section, evade Alpha’s projectiles.
  7. Heal if necessary
  8. Repeat steps 1-7 until Alpha is dead.

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Grant Testa

Grant Testa is a former Heisman trophy nominated wide receiver and Wimbledon semifinalist turned videogame journalist. Some of the awards and honors he has received include the Pulitzer Prize, the Presidential Medal of Freedom, and People’s Sexiest Man Alive. When he’s not writing for Prima Games, you can find Grant at his other job, guarding a fork in the road with his identical twin brother who only tells the truth.