Someone made a CAPTCHA where you play Doom on Nightmare difficulty - Ars Technica

1. Someone made a CAPTCHA where you play Doom on Nightmare difficulty  Ars Technica
2. Protect Your Site With A DOOM Captcha  Hackaday
3. New Captcha requires defeating three enemies or you're Doomed to repeat it  Tom's Hardware
4. Prove you're human by playing Doom in a captcha  Boing Boing
5. People are playing a new DOOM-themed CAPTCHA  TechCrunch