Important Notes

Important Notes for The Callisto Protocol

General Warnings & Pitfalls

• No Manual Saves: The game uses an automatic checkpoint system. Do not quit during an auto-save icon (a spinning circle in the corner) or you may corrupt your save file. If you must exit, wait for the icon to disappear.


• One Save Slot (per profile): You cannot create multiple manual saves. Progress is overwritten at each checkpoint. To have multiple playthroughs, use different user profiles or backup your save file manually (PC: `%USERPROFILE%\Documents\My Games\The Callisto Protocol\Saved\SaveGames`).


• Difficulty Cannot Be Changed Mid-Game: Choose your difficulty carefully. There is no way to lower or raise it after starting. Minimum Security (easy) is forgiving; Maximum Security (hard) and New Game+ are significantly tougher.


• The GRP (Grip) is Your Best Friend: Do not neglect upgrading the GRP battery and pulling capacity. It can instantly kill many enemies by throwing them into environmental hazards (spikeworms, fans, chasms). This saves precious ammunition.


• Conserve Ammo Mindfully: Ammo is scarce on higher difficulties. Melee combos (timed attacks) are powerful and do not consume resources. Use the GRP to set up melee finishers. Only use guns when necessary.


• Upgrade Wisely: You cannot respec upgrades. Focus on one or two weapons first (the Hand Cannon and Skunk Gun are popular) and the GRP battery. Avoid spreading credits across all weapons early on.


• Environmental Hazards: Spikeworms (the tentacle creatures) are instant kills if you throw an enemy into them. Use this constantly. Also note that some walls or pipes emit steam or electricity – same effect.




Irreversible Choices & Missable Content




• Collectibles are Missable: Audio logs, data logs, and Biophage lore collectibles are scattered throughout the game. Several are in areas that become inaccessible after advancing the story. In Chapter 2 ("Outbreak"), after the first tram ride, you cannot return to the starting area. Chapter 8 ("Lost") has a similar lockout. Use a collectible guide to avoid missing them.


• The Secret Ending: To unlock the secret ending (a post-credits scene), you must collect all 12 Biophage Lore logs throughout the game. Missing even one forces you to replay the entire game on the same or higher difficulty (New Game+ does not carry over collectibles progress).


• No Story Choices: The game is linear with no branching decisions. However, some optional elite enemies (e.g., the Two-Head in Chapter 5) are not mandatory to kill but drop extra credits. Skipping them is safe but you lose upgrade currency.


• DLC Content: The "Final Transmission" DLC takes place after the main story and is separate from the save file. Starting it does not affect the main game, but it has its own missable collectibles.




Difficulty Spikes




• Chapter 5 – "Lost": The game introduces the Two-Head (a boss) in a tight arena. This is the first major spike. Use the GRP to throw environmental hazards at it, and keep moving. Don't stand still.


• Chapter 7 – "Colony": Swarm encounters with multiple Biophage at once. The game ramps up enemy aggression. Use choke points and the GRP to thin numbers.


• Chapter 8 – "The Vault": The final boss (Captain Ferris) has a second phase that demands perfect dodging and quick-time events. Stockpile health injectors and ammo before the encounter. The checkpoint is just before the fight.


• Maximum Security Difficulty: Enemies deal massive damage (2-3 hits kill), and resources are drastically reduced. Enemies have more health and new attack patterns. Grinding (revisiting areas) is not possible, so every bullet counts.




Grinding Traps




• No Grinding Required: The game does not allow backtracking to farm enemies or credits. Each area has a fixed number of resources. There is no point in trying to grind.


• Wasted Credits: Do not spend credits on cosmetic items (e.g., weapon skins) early on – they offer no gameplay benefit. Save credits for upgrades and health injectors.


• Vending Machines: Use them only when you are low on essential items (health injectors, ammo). The prices increase each time you buy, so stockpiling early is inefficient.




Online Etiquette & Anti-Cheat Notes



• Single-Player Only: The Callisto Protocol has no multiplayer or online interaction. There is no anti-cheat software required. Mods on PC are unofficial and may cause instability – back up your save before using them.


• DRM: The PC version uses Denuvo anti-tamper. This may affect loading times or performance on some systems. No online connectivity is needed after the initial activation (Steam/Epic).


• No Leaderboards: No competitive features, so no etiquette concerns.




Save Management Advice




• Backup Saves on PC: Navigate to `%USERPROFILE%\Documents\My Games\The Callisto Protocol\Saved\SaveGames`. Copy the entire folder before major bosses or after collecting all logs. On console, you cannot create manual backups; use cloud saves (PS Plus / Xbox Live) before critical points.


• Auto-save Timings: The game auto-saves at chapter transitions, after opening certain doors, and before boss fights. It does not save during combat. If you die, you will respawn at the last checkpoint, which may be several minutes earlier.


• New Game+ Data: After completing the game, you can start NG+ from the main menu. It uses the same save slot, so your pre-NG+ progress is overwritten. Consider making a manual backup if you want to keep the original save.




Things Players Commonly Regret Not Knowing Earlier




• You Can Dodge Without Attacking: Hold left or right (or use the D-pad) to dodge incoming attacks. Timing is not strict – you have a generous window. Do not spam the attack button.


• Melee Combos: Press the attack button with the rhythm of a heartbeat (1-2-3 pause, 1-2-3). If you just mash, Jacob will stop attacking. Practice in the early prison cell.


• The GRP Pulls from a Distance: You can pick up objects and enemies from far away. Use this to disarm enemies (pull a weapon from their hand) or create traps.


• Health Injectors Are Expensive: In shops, they cost 300 credits. You can find them free in the world. Save your credits for upgrades.


• Weapon Skins Are Cosmetic Only: The purchasable skins do not affect stats. They are a waste of credits in a first playthrough.


• The Hand Cannon is the Best Early Weapon: It has high damage and decent ammo economy. Upgrade it first.


• Chapter Select is Not Available: You cannot replay specific chapters without starting a new game (or New Game+). Make sure to grab everything during your first run.


• Final Boss Arena Has a Secret: In the final boss room, there is a hidden audio log near the door on a desk. Many players miss it and lose the chance for the secret ending.




Platform-Specific Notes



• PS5 / Xbox Series X|S: The game supports haptic feedback and adaptive triggers (PS5) – these can be turned off if you find them distracting. No manual save deletion option in-game; you must manage saves through system storage.


• PC: The game’s performance can be uneven. Disable ray tracing if you experience stuttering. Use DLSS/FSR for smoother framerates. The PC version also has a known mouse acceleration issue – disabling it in settings helps.


• Steam Deck: The game is Steam Deck Verified, but runs at medium settings 30 FPS. Lower resolution to 720p for better battery life.




Final Advice



• Take Your Time: Explore every corner before moving on. Most resources and collectibles are hidden off the main path. Listen for audio log indicator pings.


• Use the Environment: The game is designed around environmental kills. Always look for hazards before engaging enemies.


• Don’t Hoard: Use health injectors freely; you cannot carry more than a few. Similarly, ammo types are limited, so fire when safe.


• Prepare for the Endgame: Before Chapter 8, ensure you have at least 3 health injectors and full ammo for your primary weapon. The final gauntlet is relentless.