I bought that 20% code too.
I will also buy Revelator even though I own the Japanese disc. With that 20% off it's a no brainer in addition to me having all the NA dlc when Aksys gave them out for free. I don't regret buying the Japanese disc or its dlc.
This will make KOFXIV my defacto disc as a result.
Looking at:
SFV
Revelator
Volgarr
SS6
Anyone on the fence about SS6, the PS2 port which the PS4 release is from was not only a perfect port of the Atomiswave original but iirc since it's been years, the game also has faster loading too. That's on top of extras. This also applied to KOFXI on PS2.
Only NGBC was sort of a botched port since the ps2 version loaded longer than the AW game.
And take it from me, I used to be at the forefront of the early SNKP days with the original Guardcrush.net.