There's a file within Tallowmere.app that needs to have its permissions updated. I came across this issue when creating the Tallowmere 2 demo – looks like Tallowmere 1 needs this fix too.
Manual fix for Tallowmere v350.5 if you're comfortable using Terminal.app:
1. Open Terminal.app.
2. Use cd to change to the directory where Tallowmere.app resides. If Tallowmere.app is on your desktop, you could go:
cd ~/Desktop
3. Use chmod to fix the permissions:
chmod a+x Tallowmere.app/Contents/MacOS/*
Alternatively:
Let me update the itch.io builds to v352 and I'll make sure this fix is in place. I'll post again once they're uploaded.