The Callisto Protocol is a survival horror game, so you’ll be scrounging for ammo and supplies throughout the campaign. What you might not expect, though, is that a few of its weapons are actually completely missable if you aren’t thorough in your exploration. This means that you could end the game with only two guns and a melee weapon–but that shouldn’t be a problem, since we’ve got the locations of all story and optional weapons below.

Stun Batton

The Stun Batton is automatically obtained during the Outbreak chapter and will be your melee weapon throughout the remainder of the game. You’ll snag this after a room with two giant fans and a bunch of enemies. Just crawl through the nearby shaft and you’ll get the weapon during a short cutscene.

Hand Cannon

The Hand Cannon is automatically obtained during the Outbreak chapter and is the first ranged weapon you’ll have access to. Late in the mission, you’ll enter a room where Elias will toss you part of a pistol. Take this over to the Reforge nearby and purchase the Hand Cannon to move the story forward.

Skunk Gun

The Skunk Gun is made at the Reforge by using the Skunk Gun Schematic, which is found in the Aftermath chapter. A bit into the chapter, you’ll need to find your way out of a basement. You’ll be in an area known as Basement D3, and you’ll stumble upon a fuse box that can’t be used quite yet. Continue forward through the mostly linear path until you reach an area where you have to take out some enemies and find a fuse on the floor. While your first thought would be to use this to open the nearby door, you should instead take it back to the fuse box you saw before. Use it there to open a door, then crawl through the ventilation shaft here to find the Skunk Gun Schematic in the next room.

Riot Gun

The Riot Gun is automatically obtained during the Lost chapter. After making your way through a variety of snowy outdoor locations and some inner corridors, you’ll eventually stumble into a room where you’ll find Dani fighting off a hoard of enemies. Help her clear them out, then open the door for her to trigger a cutscene where she hands this heavy-hitting shotgun off to you.

Tactical Pistol

The Tactical Pistol is made at the Reforge by using the Tactical Pistol Schematic, which is found in the Below chapter. Partway through the chapter, you’ll enter a room where three blind enemies will walk in and converge from left, right, and in front of you. Take these out quietly and head through the door ahead, following the path until you have to vault over some metal debris. At the entrance to this next room will be another enemy that will emerge from the wall. Once you’ve killed it, you can find the Tactical Pistol Schematic sitting on a desk on the right side of the area.

Assault Rifle

The Assault Rifle is made at the Reforge by using the Assault Rifle Schematic, which is found in the Colony chapter. While exploring the slums late in the chapter in search of a security key, you’ll come to a point where you have to climb a ladder attached to one of the run-down homes on the ground floor to reach the upper section. When you reach the top, head behind you to a bathroom and pick up the Assault Rifle Schematic on the sink there–and beware of the enemy that bursts out to attack you immediately after.