How to get to the fifth planet in Revenge of the Savage Planet

In Revenge of the Savage Planet, there’s a hidden fifth planet that only unlocks late in the game. Named Slappi's Den of Fun, it’s tied to the main story, and to reach it, you’ll need to finish a quest called Interstellar Enigma and collect all five pieces of an item called the Pentaforce. Once that’s done, the new location opens up.

Here’s a guide on how to unlock the fifth planet in Revenge of the Savage Planet.

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Reaching the fifth planet in Revenge of the Savage Planet

Start the Interstellar Enigma quest

Get started with the quest (Image via Raccoon Logic Studios // YouTube@Hikikomori Gaming)

This quest doesn’t unlock until near the end of the main storyline. It’s triggered through your contact with Slappi, who finally drops the act and reveals himself as you close in on the game’s climax. He assists you on a trail to track down five ancient shrine trials scattered across multiple planets. Each one holds a Pentaforce fragment. Here’s a short breakdown of the shrine locations:

• Shrine of Timing – Located west of the Habitat Base on Stellaris Prime, on a hill surrounded by cliffs.
• Shrine of Pressure – Found in the Cliffs of Abaddon area, also on Stellaris Prime.
• Shrine of Grind – Located near Cactus Pools on Xephyr.
• Shrine of Combat – Found in the underwater section of Bilodeau’s Floating Isle, in the Zenithian Rift.
• Shrine of Challenge – Unlocked after the first four; this is the final shrine and part of the quest chain, and you must face the Cyber Wardrill boss.

After collecting all the Pentaforce pieces, go back to the hub (The Habitat) and open the research computer. You’ll unlock a new Pentaforce-related research perk. Activating this perk makes the fifth planet, Slappi’s Den of Fun, available as a travel location. Once it's unlocked, interact with the Planet Cannon. This device launches your character directly to the fifth planet.

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Inside Slappi’s Den of Fun

Mecha Slappi in Revenge of the Savage Planet (Image via Raccoon Logic Studios // YouTube@Hikikomori Gaming)

After arriving at the hidden planet, you will automatically board a rail cart ride. This sequence plays out with dialogue from Slappi and multiple locked doors. To progress, shoot the purple terminals beside each door.

The final chamber hosts a boss fight against Mecha Slappi, where Slappi enters the robot's cockpit and fights back. Defeating him will unlock one of the game’s ending cutscenes. You’ll also earn the Entertained to Death achievement and get access to the Slappi toy back at your hub in Revenge of the Savage Planet.

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This concludes our guide to reaching the fifth planet in Revenge of the Savage Planet.