LiveCode (livecode.com) (ex Runtime Revolution) is a pretty good descendant of HyperCard. Cards, controls, scripts are mostly compatible. I migrated many of my old stacks to LiveCode.
The OP's link actually lets you fire up the stacks and edit them, although I don't think the state is saved when you close
The state is not saved.
It's not saved yet, but the Internet Archive is apparently working on this!