I'm waiting for them to come in cheap, but my brother bought the full pack and wasted it for himself a wee bit.
He said the Mars one was pretty good but he picked up an alien rifle that carried over into the main game when he'd barely started it, so he didn't need to upgrade weapons much.

The longest side mission for me was finding all of the Shrines.
I flew over that map for about 12 fucking hours and ended up having to look at one of the gamer maps online and fly around ticking off every location.
The mad guy making the film is pretty funny.
Jesse from Breaking Bad guy is good and I thought Hurk Drubman Sr. was hilarious...obviously based on Jackie Gleason's 'Sheriff Buford T. Justice' from the Smokey and The Bandit films.

btw...I did the Willis Huntly mission and didn't even realise he's another character that's been in the game since FC3....my 12 year old nephew had to point that out to me. (I'm so old)
