It plays Doom Someone made a CAPTCHA where you play Doom on Nightmare difficulty Surprisingly (or unsurprisingly?) this is not the first Doom CAPTCHA. Samuel Axon Jan 2, 2025 3:05 pm | 9 You must kill at least three demons in Doom to prove you're human. Credit: Guillermo Rauch You must kill at least three demons in Doom to prove you're human. Credit: Guillermo Rauch Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn morePeople have been complaining for a while that passing a CAPTCHA is too difficult, but developer and tech CEO Guillermo Rauch has made one of the hardest yet: a fully playable CAPTCHA based on the classic PC game Doom.It's been a long-running joke that developers will make Doom run on absolutely anything, so it's not much of a surprise that it's now running inside something that resembles a CAPTCHA.The app essentially amounts to a small Doom level that is playable with keyboard controls (arrow keys to move, space bar to shoot) within a CAPTCHA-like presentation. You must kill three enemies to pass the test.The level reflects Doom's Nightmare difficulty, and it is much harder than needed to be an effective CAPTCHAespecially since you can't strafe to avoid enemy fire. It took me several tries to cheese a victory, and the Hacker News thread about this app is filled with people noting how difficult it is and sharing strategies.It's a WebAssembly application, but it was made via a human language, prompt-driven web development tool called v0 that's part of a suite of features offered as part of Vercel, a cloud-based developer tool service, of which Rauch is the CEO. You can see the LLM bot chat history with the series of prompts that produced this CAPTCHA game on the v0 website.Strangely enough, there has been a past attempt at making a Doom CAPTCHA. In 2021, developer Miquel Camps Orteza made an approximation of onethough not all the assets matched Doom, and it was more Doom-adjacent. That one was made directly by hand, and its source code is available on GitHub. Its developer noted that it's not secure; it's just for fun.Rauch's attempt is no more serious as a CAPTCHA, but it at least resembles Doom more closely.Don't expect to be playing this to verify at real websites anytime soon, though. It's not secure, and its legality is fuzzy at best. While the code for Doom is open source, the assets from the game like enemy sprites and environment textureswhich feature prominently in this applicationare not.Samuel AxonSenior EditorSamuel AxonSenior Editor Samuel Axon is a senior editor at Ars Technica. He covers Apple, software development, gaming, AI, entertainment, and mixed reality. He has been writing about gaming and technology for nearly two decades at Engadget, PC World, Mashable, Vice, Polygon, Wired, and others. He previously ran a marketing and PR agency in the gaming industry, led editorial for the TV network CBS, and worked on social media marketing strategy for Samsung Mobile at the creative agency SPCSHP. He also is an independent software and game developer for iOS, Windows, and other platforms, and heis a graduate of DePaul University, where he studied interactive media and software development. 9 Comments