Warhammer 40,000: Boltgun 2 Guide | All Secrets and Purity Seals in Mountain of Skulls

Mountain of Skulls is a chapter in Warhammer 40,000: Boltgun 2 that takes you through three levels: Blood Fortress, Blood Cascade, and Blood Machine. Each level contains hidden Secrets and one Purity Seal. You will need to shoot concealed skull switches, explore side passages, and look for hidden platforms to collect everything. 

Blood Fortress: All Secrets and Purity Seal

Blood Fortress contains four Secrets and one Purity Seal. Explore the fortress walls, drawbridge area, and containers instead of following the main route directly to the exit. 

Secret 1: Machine Spirit

1. Follow the route toward the Red Key until you reach a room filled with metal structures.

2. Search the structures for a hidden skull switch.

3. Shoot the skull to open a concealed side room.

4. Enter the room and collect the Machine Spirit.

Switch to the weapon you want to upgrade before picking up the Machine Spirit, as it enhances your currently equipped weapon.

Purity Seal: Jump Pad Near the Drawbridge

1. Collect the Red Key and use it to open the red door.

2. Progress until you reach the drawbridge control panel.

3. Activate the panel to lower the drawbridge.

4. Look toward the tall structure ahead and locate the skull on top.

5. Shoot the skull to activate a jump pad nearby.

6. Use the jump pad to reach the hidden platform and collect the Purity Seal.

Secret 2: Grenade Boost

1. After crossing the drawbridge, explore the area around the fortress entrance.

2. Search the side paths and look for a concealed skull switch near the rocks.

3. Shoot the skull to reveal a hidden compartment.

4. Enter the compartment and collect the Grenade Boost.

Secret 3: Boltgun Magazine

1. Continue into the fortress and explore the lower section around the containers.

2. Look for a hidden skull switch on the metal structures.

3. Shoot the skull to open the concealed passage.

4. Collect the Boltgun magazine inside.

Secret 4: Machine Spirit Upgrade

1. Continue through the lower fortress area toward the level exit.

2. Search the containers and metal platforms near the final rooms.

3. Look for another concealed skull switch.

4. Shoot it to reveal the hidden compartment.

5. Collect the Machine Spirit upgrade.

Blood Cascade: All Secrets and Purity Seal

Blood Cascade contains four Secrets and one Purity Seal. Several collectibles require you to shoot hidden skull switches near the colored-key doors, so check the walls and ledges before moving forward. 

Secret 1: Hidden Compartment Near the Red and Purple Doors

1. Progress until you reach the area just beyond the Red and Purple Doors.

2. Climb onto the elevated platform where an enemy is firing at you.

3. Turn around and look across the gap for a small skull mounted on the opposite structure.

4. Shoot the skull to open a compartment in the wall ahead.

5. Jump across to the opening and collect the Secret. 

Secret 2: Grenade Boost Beneath the Purple Key

1. Continue through the Red Door and follow the route toward the Purple Key.

2. Pick up the Purple Key, then look to your right across the chasm.

3. Shoot the skull switch on the structure opposite the key platform.

4. Drop down from the key's ledge and turn around.

5. Enter the newly opened alcove and collect the Grenade Boost. 

Secret 3: Machine Spirit Beyond the First Yellow Door

1. Find the Yellow Door and unlock it.

2. Cross the bridge beyond the door until you reach the large drop.

3. Look down into the hole ahead to spot a skull among the spikes.

4. Shoot the skull to open the barred compartment.

5. Drop onto the lower platform and collect the Machine Spirit. 

Purity Seal: Hidden Platform Near the Second Yellow Door

1. Complete the Purge encounter beyond the first Yellow Door.

2. Leave the arena using the path on the right, leading toward the second Yellow Door.

3. Look around the chasm beside the door for two hidden skull switches.

4. Shoot the skull above the door switch, then shoot the second skull high on the opposite side.

5. Wait for the platform to appear.

6. Jump onto the platform, enter the alcove, and collect the Purity Seal. 

Secret 4: Infinite Ammo in the Final Arena

1. Pass through the second Yellow Door and enter the large arena.

2. Fight through the enemies while watching the small side rooms that open around the arena.

3. Enter the second room on the right before its floor collapses.

4. Find the skull inside and shoot it to reveal the pickup.

5. Collect the Infinite Ammo bonus to finish Blood Cascade. 

Blood Machine: All Secrets and Purity Seal

Blood Machine contains four Secrets and one Purity Seal. The collectibles are hidden around the blood-filled shafts, destructible growths, and machinery surrounding the three large structures. Save before attempting the first Secret, as the drop is easy to miss. 

Secret 1: Hidden Ledge in the Blood Shaft

1. At the beginning of the level, follow the tunnel until you drop into a blood-filled shaft.

2. Continue until you reach the second drop.

3. As you fall, pull backward to land on a narrow ledge halfway down the shaft.

4. Collect the Secret on the hidden ledge before continuing.

This Secret is easy to miss because you must move against the direction of your fall to reach the platform. 

Secret 2: Hidden Pickup Near the Red Key

1. Continue through the level until you reach the large structure containing the Red Key.

2. Climb the structure and inspect the surrounding machinery.

3. Look for destructible growths or nodes attached to the structure.

4. Destroy the correct node to reveal the hidden Secret.

5. Collect the pickup before continuing toward the Red Key. 

Secret 3: Machine Spirit on a Pipe

1. Reach the room where you collect the Red Key.

2. Turn left and enter the small adjoining room.

3. If the entrance is blocked, destroy the nodes surrounding the doorway.

4. Enter the room and look to your left.

5. Collect the Machine Spirit resting on the pipe. 

Secret 4: Hidden Room Behind a Blue Panel

1. Use the Red Key to open the corresponding door.

2. Continue through the connected semicircular rooms.

3. Stop in the short corridor between the two large rooms.

4. Find the blue wall panel and shoot it.

5. Quickly run through the door that opens temporarily.

6. Collect the Secret inside before the door closes. 

Purity Seal: Hidden Room Near the Purple Key

1. Continue through Blood Machine until you reach the structure containing the Purple Key.

2. Search the small room to the left of the key.

3. Destroy the surrounding nodes to open the entrance if necessary.

4. Enter the room and collect the Purity Seal.

Make sure you collect the Seal before leaving the structure to continue toward the Yellow Key. 

Final Thoughts

Mountain of Skulls contains 12 Secrets and three Purity Seals across Blood Fortress, Blood Cascade, and Blood Machine. The most important things to remember are to shoot skull switches beside locked doors, check below platforms before jumping forward, and look for destructible nodes around the machinery.

Check the collectible counter before finishing each level. If you miss an item, use Level Select to replay the level instead of restarting the campaign. 

FAQ

Q. How many Secrets are in Mountain of Skulls?

A. There are 12 Secrets: four in Blood Fortress, four in Blood Cascade, and four in Blood Machine.

Q. How many Purity Seals are in Mountain of Skulls?

A. There are three Purity Seals, with one in each level.

Q. Which Secret is easiest to miss?

A. The first Secret in Blood Machine is particularly easy to miss because you must move backward while falling through the second blood shaft to land on a hidden ledge.

Q. Can you return for missed collectibles?

A. Yes. You can replay completed levels through Level Select to find any missing Secrets or Purity Seals.