If it's telling you that it cannot be opened, run this command in Terminal:
- chmod +x /Applications/MarioVsLuigi-MacOS.app/Contents/MacOS/NSMB-MarioVsLuigi
If it's saying that it could not be opened because "Apple cannot check it for malicious software", right click and hit open instead of double clicking.
For more help, join the discord at https://discord.gg/dgKVaUKpj5 and post a message in #technical-support