Yes, I did build it myself with the Ozmoo web page from the z-file.
I am running on a real C64 with a 1541 Ultimate II+. I have the 1541U’s REU emulation enabled and I'm loading from disk images.
For the save disk I created a separate disk image which I mount when required.
A previous build used to work with this same exact setup. Not sure when exactly it was broken, but I have a vague recollection that Ozmoo was updated sometime last year perhaps? If this is down to Ozmoo (which makes sense now that you say it), then that would match with when it last worked for me.
I would like to help the Ozmoo guys in testing this, but I'm not sure how to contact them without sharing my email in the open… If they happen to use Mastodon, they can DM me: https://mastodon.gamedev.place/@harri
If they don't, they can get my email by placing my first name on the left side of the @, and my verified website URL on the right side :-)
Thanks for the reply! It's an awesome game, so I'd like to keep playing it, even though I actually have to start from the beginning now :-) After the REU experience, it's just hard to go back to stock C64…