Mac files are usually unzipped by default. However, the file is showing as an application, and not as a .dmg disk image. For applications containing a lot of files, it is better to use a .dmg.
Viewing post in Base Dolphin jam comments
Ohk, I'm sorry for bothering you, I should have researched about it before. When I exported the game, it created a folder named "Base Dolphin macOS.app". And then I compressed it as a .zip file. I assumed .zip files were popular in the macOS environment too. I guess I will make changes after the jam, for now, you can try downloading from the link given below if you are interested https://drive.google.com/drive/folders/1awvRPtq1oPOJA1sANznAHQrNQftMszbr?usp=sha...