Hey there! The Mac version doesn't start by default. The standard error pops-up:
"The application “Seamlessifier.app” can’t be opened."
I checked by running through terminal and the app doesn't have permission to be an executable, so people should go to the directory they got the .app in and run this command in the terminal:
chmod +x Seamlessifier.app/Contents/MacOS/Seamlesifier
As a developer there are a bunch of ways to fix it, which mostly comes down to using an archiver which preserves flags.
P.S. there is a typo in the binary itself, it uses 1 "s" versus 2 in the app name, which is kinda annoying lol.