You can implement delimited continuations with regular call/cc and a mutable cell. Of course, like all abstractions based on raw call/cc, it's not modular: you can't do that and use the result inside, for example, a multitasking scheduler that itself uses raw call/cc as well.

http://okmij.org/ftp/continuations/against-callcc.html#traps

Closer to your point, there are a few other implementations that offer delimited continuations natively. See https://wingolog.org/archives/2010/02/26/guile-and-delimited... for a 11 year old post on adding them to guile scheme.