Can you try these instructions and let me know? Apologies for the inconvenience.
1) Open the Terminal app.
2) Copy and paste this command into Terminal: chmod -R 755
3) Then drag the Malevolent Planet icon into Terminal. When you release the mouse button, the path to Malevolent Planet appears in Terminal
4) Press return.
5) Malevolent Planet will now run properly when you double click the icon