Station 51 is a single player mod for Half-Life 2: Episode 2. You are on the run from the Combine closing in on your outpost. Can you escape?
Awesome mod. Great map design, feeling for details and well thought out situations. A mod does not need hard puzzles or complicated story to tell to be fun. This is pretty simple, run and shoot most of the time. I wish there were more mods like this one.