The last version of the rules from ironbros.gg before it shut down:

IronBROS Challenge

IronBROS is a deathless challenge for Endless Mode in Super Mario Maker 2 created by GrandPOObear. Here are the rules:

1. The goal is to beat 50 consecutive levels on Normal. No skipping is allowed.
2. You have one life. If you die, you reset.
4. If you want to turn comments on or off, you must do so at the start of the attempt. For the full run, comments must either be always on or always off.
5. No translating level titles at all. This includes Google Translate, chat, and so on.

Frequently Asked Questions:

Q: What happens if I accidentally pause during a level?

A: Don't sweat the small stuff. As long as you're not gaining an advantage from it, you're fine.

Q: Am I allowed to use external tools to find out info about a level?

A: Nope.

Q: Who is this challenge for?

A: It's for The People.

Q: How's the trademark going?

A: We're working on it.

Q: What should I do if my favorite IronBros creator is not currently live?

A: You should subscribe to their YouTube to stay up to date on all their content.