Hehe fun!

Yeah, delimited continuations have much saner semantics than undelimited ones. Partly because they’re always well defined

I like the notation "limited continuations" more than "undelimited". Drops the double negative and provides a pejorative element.

Call/cc still has a delimiter, it's just some second class thing above the scope of the current program that you can't do much with which thwarts composition. Let the programmer specify where the delimiter is and you get a less limited construct.

"undelimited" is not a double negative. "Delimited" means "limited by an explicit boundary."

Introducing a different concept with the same word "limited" is confusing.

"specifiable continuations" may be a clearer way to make a positive connotation.

Yes. It's also pretty clear how to use delimited continuations in a pure setting without mutation.

I'm not quite sure you can make use of something like call/cc without having at least one mutable variable or side-effect somewhere?