As Ian carefully explained back in May, Goat of Duty is "Call of Duty but with goats". Hence the name, I suppose. And let's not get into why this particular shooting game stars goats, or why, in general, game developers like to include goats in their games. Let's just stick to the facts, shall we: Goat of Duty is available to play in Early Access right now.
According to the Steam page, you play as an armed goat, and the objective is to kill other armed goats. The game supports up to ten players, and you can even dress your goat in different types of costume. To be honest, the movement and shooting in Goat of Duty more closely resembles an arena shooter, but don't let the truth get in the way of a good play on words.
The Early Access build boasts four modes: free-for-all, Gun Deathmatch, Herd Wars and Fus Ro Arena (I'm not sure what the latter is). The studio 34BigThings expects the game to launch into 1.0 within the next four or so months, and the dev roadmap includes more maps, modes, "goatstumes" weapons and more.
Here's a trailer: