Hi, i played this game back when I was a kid at Nintendo DS. Is emulator allowed?

I have no problem with emulator use as of right now. I've tried the game out on emulator myself and I don't recall any major advantages. Rather, it was actually much, much harder to do the card minigames with a mouse.

And in general I'm of the opinion that emulators are totally fine for any game with less than a dozen runners. IMO, it's more a matter of encouraging play than being as accurate as possible, especially considering the state of DS screen capture.