I'm a mac user. Every time I download and open the game, I get a 'damaged, moved to trash' message. What is this?

What this usually means is that you are trying to run an application whose signature does not match the application itself . This could be an application that is trying to do something evil and the OS doesn't want to let you run it.

I had good luck running Afterlife from the command line. What I did was drop into the terminal and cd to the Afterlife/Contents/MacOS folder where you will find a file called "GOGLauncher". I started GOGLauncher from the command line and was able to run the game.