I got a similar error. You may be able to solve it by doing the following: right/two finger click the app, click Show Package Contents, double click the folder Contents and then right/two finger click the folder named MacOS and hover over the bottom option Services. In the Services menu, select New Terminal at Folder. It should open up the terminal app. When there, copy and paste "chmod +x Junkworld" into the terminal and press enter. You should be good to go! I hope this works for you :)
Note it also could be because the app's architecture isn't for M1 macs, and in that case you are sadly out of luck. Afaik there aren't any easy ways to run Intel apps on M1 macs
