Shadow focused decks got a lot of good new cards in Expedition. I added some time and took it from rank 37 to 3 with an 8:0 score. The playstile is relatively straightforward, the hardest thing to evaluate is the powerbase. Try to focus on Shadow to get to 3 on 3 and 4 on 4, but dont take hands without time (only if you can plunder into it). You have a lot of flexible early game removal, you can also swap some of them (alternatives are cards like
Defile,
Scorpion Wasp and
Swirl the Sands) if you feel like they are bad against the decks you usually see. Your winconditions are several big units that have mostly some form of evasion or ETB effects (The dream wincon is
Karvet, Redeemed into
Severin of the Dark). The market has some additional winconditions, mixed with different kind of hate effects.
Good luck and have fun!