Are you referring to the app? I didn't know itch.io had one until just now. I looked into downloading it for troubleshooting, but it's not available for my device.
What I've done on my end is uploaded another file (enthralled1.1.2.html), made it the primary file, and gave it the same settings as the last file. I'm not sure why it wouldn't be installable. Do you need the older file?