You should only really get Seal the Deal if you're a massive AHiT fan or really looking for more difficulty from the game. The chapter it adds is alright, but it doesn't really have the fun platforming of previous worlds and some of the missions are eh. Death Wish is a neat concept, but it does kinda get annoying to deal with whatever annoying difficult challenge the game forces you to go through - I do realize that this is just because I'm not that great at hard challenges though, so a masochist would love it.