i tested few things of BD nightmare.
for example 6K wow this move seems to be so dangerous in BD, after CH 6K you can do the 1A or 44BB tech traps, if you try to ukemi the 1A will knock you down again, allowing GS KK, for a 79 damage combo, otherwise if you stay in the ground trying to stand on reaction (by seeing the 44BB) and you don't ukemi, the 44B(B) will hit you in the ground, allowing NSS > GS B for a 93 Damage combo.
they change nightmare's Guard Crush game, here a rapid list of the few strong GC moves in BD
8 -A+B+K > unsafe
9 -66B+K > safe
9 -66A+B > unsafe
11 -1(A) > safe
nerfed ones
GS B i dont know why :S
aB
44B
66B
33>99A
44A
44K
2B+K
whatever, the GC game of the entire game was nerfed :P, but i have the impression that in BD is much possible to perform a CF with nightmare than SC4
another good thing is the timing on the CH GS A > a(B) > NSS K > 2A+B combo is so much easier to perform.
well, ill keep checking things on BD, peace