In Chapter 18 of DOOM: The Dark Ages, players find themselves in one of the most repulsive locations—inside a monster known as the Beast's Belly. Here, you'll not only have to fight demons but also navigate through the innards of a giant creature—with floors covered in bile, convulsing organs, and a constant sense of biological claustrophobia. It's disgusting, no doubt, but it's also where you'll encounter one of the puzzles that might pose a challenge—the toothed door.

What is the Chapter 18 Teeth Door puzzle in DOOM: The Dark Ages?

As you make your way through the fleshy passages of the creature, you'll eventually come across a corridor with huge, snapping teeth. At first glance, it seems like a typical timing puzzle—you just need to calculate the right moment and run through.

But if you try to dash, jump, or even slow down time through the weapon menu—the result is always the same: the jaws snap shut, you lose some health, and you're thrown back to the start of the corridor. No timing trick will work here.

The game seems to intentionally punish any attempts to bypass the puzzle. Slowing down through modifiers? That only increases health loss. Even experienced players trying to "break" the mechanics find themselves at a dead end. This is intentional, as the only way through the door is by interacting with the environment.

How to get past Teeth Door DOOM: The Dark Ages in Chapter 18

To pass through the toothed door without being chewed up, you'll need to use the Doom Slayer's tools—specifically, the shield-saw. Stand in front of the corridor, but don't go inside. Look up and slightly to the right—you'll notice a glowing blue gear mechanism in the fleshy wall above.

Once you see it—switch to the shield-saw. Throw it directly at the gear. If you hit it precisely, the mechanism will start to turn, the teeth will snap one last time, and then lock in the open position.

The trap will be deactivated, allowing you to proceed safely. No guessing, no dashing—all you needed was keen observation and a precise throw.

What's beyond the toothed door in DOOM: The Dark Ages

After passing through, you'll find a narrow tunnel scattered with 14 gold coins. At the very end is a ledge you can climb.

There you'll find the Symbol of Life, which increases your reserve of extra lives. Most importantly, this is one of the six secret areas in the chapter, essential for perfectionists aiming to complete the level and the game as a whole at 100%.

From the upper ledge, you can see a green target for the shield's charge. Hit it to return to the main route and continue your journey through the creature's innards.

Is there another way to get through the toothed door?

The short answer is no. Or at least not in the actual game. The system is specifically designed to prevent "breaking" the puzzle with force or tricks. If you try to use time-slowing or modifiers while the trap is still active, the result will not only be ineffective—the developers anticipated such player behavior and made sure to deter any attempts to bypass it. Therefore, interacting with the blue gear is not just the correct solution; it's the only way into the secret room.

Thanks to this Teeth Door puzzle guide DOOM, you will be able to achieve 100% Belly of the Beast walkthrough.