Goat Simulator is Unreal Engine 2.

Unreal Engine 3, actually. The generation (with various iterations) from Unreal Tournament 3, Gears of War, and Bioshock Infinite.

Unreal Engine 2 would be from the period of UT 2k4 and Killing Floor.

Unreal Engine 2 is still quite heavily used especially platforms quite heavily, UT2004 was UE 2.5.

AAA console PC titles also still use it I think the most "recent" ones would be Bioshock 1 and 2. https://www.unrealengine.com/showcase/bioshock-2

Since UE 2 was ported to IOS (Don't recall if it has an Android port also) it actually became quite popular both in porting old games and in making new ones since it's a bit more optimized and is considerably easier to use than UE 3/4.