Here’s a video showcasing some details not previously mentioned about this content;

Yikes! I was a bit blasé about this add on pack but now I’ve seen it has extra levels and yes. A gun. It’s made it a must buy! There are even rumours of extra trophies to be included.
Its out December 23 in America ($6) and Christmas day (December 25) in Europe (price TBC) and Asia (600 yen).