Please read these instructions carefully and follow exactly.
Sadly Apple continues to make launching non-app store applications more difficult:
1. Click the Mac icon and download the dmademo.dmg file
2. When the download is complete, open the download folder.
3. Double click the dmademo.dmg file to mount it.
4. In the window that has popped open drag the dmademoGame icon to Applications in Finder.
5. Open up Applications in Finder.
6. Double click on the dmademoGame icon.
7. A warning stating “dmademoGame cannot be opened because the developer cannot be verified" will appear. Click cancel.
8. Control click the dmademoGame icon and click open from the menu. This time you will be given a warning and a choice to open the application. Click open.