Dino D-Day is a Half-Life 2 free mod released as prototype to an upcoming full comercial game that will be released next year.

World War 2 fiction, the axis is using dinossaurs as weapons agains allies!
Kinda confusing, but basically it means you can play this mod for free if you have Half Life 2, and can expect for a full story with full game with Dino D-Day as a part of it next year.
Designed by Abe Scheuermann, you can check more info on it at ModDB’s official Dino D-Day post!

Source: IndieGames