DoomsDay by ElectricBass 100% (Hard Demon)
I'm glad this was reverted from its ridiculous extreme state, but this is still pretty weird. I had to beat it on 60hz because it's still 144hz bugged, but it wasn't absolute agony to complete or anything even then. Just a randomly rated Catacylsm clone from 2.0 that's only as well-known as it is because the creator decided to ultra buff it and no one did anything about that for a couple years ;)
Total Attempts: 474
Demon Number: 3,093
In-Game Rating: Hard Demon
Personal Rating: Medium/Hard Demon