Operation: Aliens was a project made by Wes Desjardins. It was his eighth mod. A 1-level demo was released in March 2003, and withdrawn one year later.
Screenshots and a number of updates in February and March 2003 indicate that this was quite an ambitious project. Though it was stated that 14 levels were made, only the 1-level demo survived.
The EXE was based on registered Wolfenstein and many sprites and sounds were changed, mainly originating in the Alien Wolf patch.Download Operation: Aliens Demo at DropBox (hosted by Thomas Weiling)