The most recent Linux update is 32-bit, which isn't strictly compatible with most modern Linux configurations without installing a lot of i386 packages.
I foolishly left automatic updates switched on, so the 32-bit version was installed and now seems to be given precendence by the itch.io client when I try to run it. It fails, most likely for reasons of the aforementioned dependency hell.
While I can still run the 64-bit version from the command line or work out what I need to get the 32-bit version working, it would be really great if we could have a 64-bit Linux update if you get the time.
Thanks very much!
Owlbear wanders off to ./HypnOS