IF YOU HAVE PROBLEM RUNNING IT ON MAC
Download the zip, unzip it, open a terminal in that directory and launch these two commands:
chmod +x beat-domain_MAC.app/Contents/MacOS/beat-domain xattr -r -d com.apple.quarantine beat-domain_MAC.app
Otherwise the system will complain about "not having permissions". The reason this happens is that it was built on Windows and the app has not the permission to execute.
I hope this helps somebody, I was so obsessed by this game I had to try it on the Mac I use at work to get the full experience (was too hard otherwise).
Having played it fully, I really appreciated it (even though in normal it is somewhat too easy on most parts of the song, since you can just stay in a corner and avoid all bullets, while it would have been better if the bullet pattern would force you to move constantly - and the hard mode is just impossible for me). The music is just terrific, I think that if you continue to improve on it this could become a really cool rhythm game!