The quick fix for this problem is to move the app (either Retrobatch or Acorn) to your Desktop, launch it, quit it, and then move it back to the Applications folder.
There’s a little bit of data that’s put on apps that are downloaded that says “This app is possibly dangerous, let’s restrict it quite a bit”. It’s known as a “quarantine flag”.
In theory, moving it out of the Downloads folder to your Applications folder should remove it, but sometimes the Finder doesn’t feel like doing that.
I’ll have to play with downloading it directly to the Applications folder. Is Safari doing this for you automatically, or are you choosing the “Download Linked File As…” contextual menu item when used on a link?
-gus
(Update: Yea, downloading it directly still puts the “com.apple.quarantine” flag on it).
You can quickly remove it by pasting the following in the Terminal app:
xattr -d com.apple.quarantine /Applications/Acorn.app
xattr -d com.apple.quarantine /Applications/Retrobatch.app
Or the Desktop trick as mentioned above will do it as well.