ETC2 is a single player mod made by DaveJ for Half Life. Set within the Half Life universe, it brings back Gordon Freeman to fight against aliens, zombies and soldiers.
I've had people asking "where is ETC1?" so I decided to upload it here, rather than create a separate MODDB listing for it. ETC1 is sort of a "chapter 1" part of the ETC story, not that either mod is official canon.