He bought the masquerade from the BM before you bought Sea Hag. Against his Scrying Pool + Masquerade + random actions deck, you did not want 1 curser. Note how the game ended with YOU having 2 curses, the trash 2, and him having 0.
You were a little unlucky to keep drawing your chapel together with the BM and Sea Hag, but with a small deck, that's bound to happen sometimes.
You had a nice opportunity for double tactician with the BM and the vault. Keep your deck trim, get a little drawing power, with say, some scrying pools, and you should be able to pull it off a few turns of the game.
I think the key to this board was the scrying pool