So the Japanese Pokemon Stadium 2 (their equivalent to the first one everyone else got, not Gold/Silver) has 64DD compatability according to the product code. For anyone with a 64DD and a Japanese copy of the game, what happens when you boot the two together?
nothing most likely, as it was meant to have been a 64DD game but was cancelled in favour of a cartridge version.
If the product code is anything to go by (and it seems to be), it should still have 64DD hooks in the code. If it does anything is up in the air.
Pocket Monsters Stadium 2 (CP2J) is compatible 64DD, if you put the correct disk, game will try to load data from disk, just like Pocket Monsters Stadium 1. All informations about error messages and expansion informations are on my blog.
