I can understand not jumping in. It feels pretty daunting to debug so many languages. Just learning enough to figure out where to place new code is kinda tough. Maybe we should create kind of a general information post.

the issue being that I'd need to rearrange the start of the polyglot quite heavily, which touches almost every language

the basic idea is to exploit the fact that some languages treat carriage returns as newlines and some languages don't; that gives you an extra dimension to split along

the first line from a newlines-are-the-only newline perspective would then become very, very long

and be a whole polyglot of its own delimited by carriage returns

the "carriage returns on their own are newlines" and "carriage returns on their own are just garbage characters" language groups seem like fairly similar sizes

anyway, the reason why this may work for Lua is that Lua ignores the first line (only) if it starts with #, and doesn't treat carriage returns as line breaks, so hopefully you can split off enough languages in the first line to start the second line with valid Lua

perhaps we should make a list of languages that would benefit from rearranging the first line, and try to incorporate them all at once

Nice idea, I want to try it some time in the future. \r vs \n is something new, reminds me of /* vs # added by Chance in C++ answer.