The current rules for 1 char seeded say the goal is "trigger the credits." It used to be the same goal as all the other categories (beat the chest), but people started submitting a lot of Mega Satan runs, so I changed it. I didn't think about the fact that you can also trigger the credits by beating Isaac without the polaroid or Satan without the negative.

It seems undesirable for those kinds of runs to count, so I want to change the rule to "Beat Blue Baby, The Lamb, Mega Satan, or Delirium (and enter the chest that drops, if applicable)"

Any thoughts?

Well, chest drops on all 4 of them, so it would always be applicable :P

Sounds ok to me :)

I don't like your proposed rule change. I think it makes more sense to be either "Beat Blue Baby" or "any%" (with a 1,000,000% save file).

The Zamiel's run is okay or no?

He ended in the Isaac.

All old BoIR has "Beat the chest" as rule.