The Latest Version of 'Doom' Is a CAPTCHA (2025)

Doom may be over 30 years old, but people aren't sick of it yet. On the contrary: Fans have ported the action horror game to just about platform imaginable, from graphing calculators and treadmills to pregnancy tests. If it has a screen, it can probably run Doom.

Given that, perhaps it isn't all that surprising that the latest port of Doom is designed to run in your internet browser. In fact, there are likely dozens of ways to access the original Doom online. What makes this version unique, however, is that you aren't just playing in a browser window, but in a CAPTCHA window.

CAPTCHAs are, of course, the minute challenges you're hit with when trying to access something on the web that are intended to prove that you are, indeed, human, and not an automated bot. Some of the earliest CAPTCHAs asked you to type out a distorted series of characters—something a robot (or perhaps, these days, a generative AI bot) would struggle to bypass itself. Since then, these types of challenges have advanced to cover a wide range of puzzles and tasks. Now, that includes a playable version of Doom.

Doom is surprisingly fun as a CAPTCHA

As reported by TechCrunch, the 1993-style CAPTCHA was built by Guillermo Rauch, CEO of Vercel. The company just so happens to have an AI website builder, which Rauch used to build this port. You can try it out for yourself here.

Although the game came out over three decades ago, and this version offers but a snippet of the full experience, this CAPTCHA version of Doom is not easy. The goal is simply to kill three enemies before the enemies kill you. You can use the arrow keys to move forward, backward, left, and right, and the space bar to shoot. That's it. However, as soon as you walk forward, enemies start firing at you, and death is close at hand.

Part of the reason for the difficulty is the sheer amount of firepower coming at you from all directions. The CAPTCHA is set in a small arena, with a horde of monsters in a cage in the center, all flinging fire your way. There are four corridors leading out of the arena, all featuring even more enemies shooting at you.

How to beat Doom: CAPTCHA Edition

I can offer three pieces of advice from my short experience playing this CAPTCHA: One is to keep the space bar held down, to fire off as many shots as you possibly can. DOOM doesn't care about accuracy, so your objective is to simply face an enemies while shooting in order to hit them. The second is to ignore the enemies in the center cage: There are simply too many of them, and you'll quickly be overrun by fire. You're better off running past and trying to pick off the enemies in one of the corridors instead. As the monsters in the cage will be firing after you, they may hit and kill some of the enemies in the corridors, which won't contribute to your kill requirements, but will give you a split second of breathing room to target another enemy.

Finally, I suggest taking at least one turn to run around the cage as many times as you can. You'll last longer than you'd expect, and you can watch the monsters in the cage mow down a ton of corridor enemies. Play your cards right, and you can use this tactic to snag three kills of your own, and win the CAPTCHA. Unfortunately, since there's no site to visit, you don't really win anything other than the game contained within. At least you've proved you're human.

As TechCrunch highlights, this isn't even the first time Doom has been ported to CAPTCHA. Miquel Camps Orteza made the game a CAPTCHA back in 2021, but that offering was much more limited. Instead of being able to run around a small map, that CAPTCHA simply had you pick off immobile enemies one-by-one until you reached the four-kill quota. If you prefer your Doom: CAPTCHA to have more challenge and heightened stakes, stick with Rauch's.