The Callisto Protocol is a brutal survival horror experience that requires strategic play, efficient resource management, and the right weapon upgrades to ensure survival. Whether you’re struggling through Black Iron Prison or trying to optimize your playthrough, these seven advanced tips will help you breeze through the game.

---

1. Get the Skunk Gun as Early as Possible

While the Stun Baton and Hand Cannon serve as solid starter weapons, the Skunk Gun is an incredibly powerful one-handed shotgun that can be obtained much earlier than intended. Here’s how to grab it early:

• During the Aftermath chapter, you’ll be forced into the basement due to a broken elevator.
• Locate D3 Basement Storage, which is locked and requires a fuse.
• The fuse is found further into the basement, after the D4 Storage area, following an enemy encounter.
• Instead of proceeding forward, backtrack to the D3 Storage room, insert the fuse, and unlock the door.
• Crawl through a vent inside to find the Skunk Gun Schematic.
• Take the schematic to a Reforge station and craft the Skunk Gun for 800 Callisto Credits.

This early Skunk Gun acquisition significantly boosts your damage output, making encounters far more manageable.

---

2. Aim for the Legs to Disable Enemies

As enemies become stronger and mutate, they become much harder to kill. The best way to neutralize fast or aggressive foes is by shooting them in the legs:

• A Skunk Gun or Riot Gun can blast an enemy’s leg, forcing them to crawl.
• Crawling enemies are much slower and easier to finish off.
• This strategy saves ammo and allows for easy stomping executions.

Disabling enemies rather than trying to tank their damage can make a significant difference in your survival.

---

3. Upgrade Your GRP (Gravity Restraint Projector) ASAP

The GRP is one of the most powerful tools in the game, allowing you to instantly kill enemies by throwing them into hazards. However, its energy is limited, so upgrading it early is crucial.

• Priority upgrades:
  • Increase the Power Meter – Expands your GRP energy capacity so you can use it more frequently.
  • Upgrade Velocity – This enhances the throwing power, making enemies fly farther and hit obstacles harder.
  • Recharge Speed – Can be upgraded later, but improves recovery time when you need it.

Since GRP lets you instantly kill enemies by throwing them into spikes or grinders, maximizing its efficiency is a game-changer.

---

4. Unlock Boom Bullets for the Hand Cannon

Upgrading the Hand Cannon early is a wise investment, and maxing it out unlocks the Boom Bullets—an alternate fire mode that causes bullets to explode after a delay, dealing massive damage.

• Boom Bullets allow for high burst damage, making tougher fights much easier.
• Even Corruptors (quick enemies that hit and run) can be one-shot with a Boom Bullet followed by a melee strike.
• Hand Cannon ammo is common early on, making this upgrade even more valuable.

Since the Boom Bullets upgrade provides crowd control, it’s a fantastic mid-game enhancement.

---

5. Manage Inventory Wisely

Inventory space is extremely limited, so managing what you carry is critical.

• Ideal inventory setup:
  • Two Health Injectors (three is excessive).
  • Pristine Energy Converters for selling at Reforge stations (great for credit farming).
  • Minimal Battery Packs, especially if your GRP is already upgraded.

By prioritizing sellable resources early on, you can afford upgrades faster while ensuring you always have healing items on hand.

---

6. Maximize Environmental Kills to Conserve Energy

Instead of throwing enemies into spikes or grinders with the GRP (which consumes energy), try this trick:

• Stand near a grinder or spike wall.
• Pull an enemy close to you instead of throwing them.
• Use a melee attack while they are lifted to knock them into the hazard.

This allows you to instantly kill enemies without draining GRP energy, letting you save your power for tougher fights.

---

7. Always Double Tap (Stomp on Enemies)

Stomping on downed enemies is a crucial part of The Callisto Protocol since it yields valuable resources like ammo, credits, and health injectors.

• Even enemies impaled on spikes drop loot.
• If an enemy is stuck on a spike, you can still make them drop loot by hitting them with the Stun Baton.

This ensures you don’t miss out on free resources, especially in later parts of the game where spikes become more common.

---

Final Thoughts

By following these seven advanced strategies, you can make The Callisto Protocol significantly easier to navigate. Prioritizing early upgrades, mastering GRP mechanics, and utilizing environmental kills can make even the toughest encounters more manageable. With careful inventory management and a focus on powerful weapons like the Skunk Gun, you’ll stand a much better chance of surviving the horrors of Black Iron Prison.

Summary of Key Takeaways:

✅ Get the Skunk Gun early for massive damage output. ✅ Shoot enemy legs to slow them down and conserve ammo. ✅ Upgrade the GRP to maximize instant kill opportunities. ✅ Max out the Hand Cannon for explosive alternate fire. ✅ Prioritize inventory space for sellable items and health injectors. ✅ Use melee knockbacks instead of GRP throws to save energy. ✅ Stomp all downed enemies—even those impaled—to maximize loot.

With these strategies in mind, you’ll be well-equipped to take on The Callisto Protocol’s toughest enemies and survive Black Iron Prison. Stay sharp, use your resources wisely, and don’t forget to stomp!