@mmiler My initial idea was to create a domain specific language (or reuse an existing one) to allow text adventure games to be written on a modern machine yet also be playable on 8-bit home computers.
While I was exploring the existing options, I found that most of the popular existing cross platform systems used some type of virtual machine.
Whilst looking into virtual machines I had the idea of using BASIC instead of (or even in addition to) a DSL. The main reasons being that it would be more familiar to retro computer owners and that it could be used for other text-based programs.
It would also allow existing BASIC programs to be converted for use on multiple 8-bit computers more easily.
Text adventures were popular on tape-based computers in the 1980s. Some companies managed to squeeze over 200 locations in their games, which seemed to be enough to keep players occupied.
Disk drives were quite rare in the UK at that time, and those that were available cost almost as much as the original computer. Most households already owned a cassette recorder though.
These days, you can buy digital recorders reasonably cheaply that can be used with many 8-bit computers if you have the correct lead. There are also devices that can convert physical cassette tapes to digital files and vice versa.
As IsaacKuo mentioned, there is also software available to convert audio files to and from digital formats.