I just downloaded the DMG from the web site, opened it in Finder, and opened the "Artemis" app there. (MacOS didn't want to open it because it wasn't signed, but I overrode this.) The app started to open, but immediately was gone. I'm not sure if it crashed or exited. This is reproducible. When I move the file from the DMG to the "Applications" folder, it opened up fine.
I just downloaded the DMG from the web site, opened it in Finder, and opened the "Artemis" app there. (MacOS didn't want to open it because it wasn't signed, but I overrode this.) The app started to open, but immediately was gone. I'm not sure if it crashed or exited. This is reproducible. When I move the file from the DMG to the "Applications" folder, it opened up fine.
This is on MacOS Catalina 10.15.7.