Breaks my heart to say no at this point. But that has nothing to do with the computers itself. I chose to go for the Z-machine version 5 with Ghosts, or XZIP as Infocom used to call it, purely to create better and bigger games and work around the many limitations that come with z3. The CoCo is unfortunately one of the very few computers still out there where no Z-machine version 5 interpreter is available. But I know you're good connected and the CoCo community is super big... the sources of the Infocom interpreters have recently been published. If someone on the CoCo Discord for example is capable to make the interpreter work with z5, I'd be more than happy to add CoCo to the list of supported systems https://github.com/erkyrath/infocom-zcode-terps