IOS?
Want to check if this is a specific IOS problem, as some Mac user were able to play it.
Viewing post in Shuggerlain v0.61.1 released! comments
This is a copy+paste of a user that made it work on different MacOS:
While this update is downloading I have been doing some thinking and I'm pretty sure its still the "not identified developer" error. And while looking at the macOS version which is Ventura or 13.0, its System Settings panel is different from 12.6 and lower so people who have have 13.0 and up wouldn't have the options that I previously presented.
So I downloaded .61 and opened it and I got the same error as before, so then I looked up how to get passed it on this version of macOS and so all you got to do is "control click > open the application" and then another popup should come up says that you want to bypass apples malware protection and all you got to do it click open. And it worked for me, game ran same as usual, h-scenes worked. Will work with 14.1.1 I believe too.
Basically malware protection/unidentified developer is what is making some Mac user are having problem to start it. You need to bypass this extra protection macOS has by default.