Hi. I don't speak english so i'm sorry if i cannot express like i want.

I'm interesed in this game. I want practice and do some decent run in hard difficulty (no shurikens)

But i'm preffer use Kega fusion instead BizHawk, because my pc is basically a potatoe and usually have a little input lag.

Is this allowed? i can use Kega fusion? Is there a particular version I should use?

Thanks.

Yes, Fusion is allowed. Looks like there are a few runs on the board which use Fusion 3.64. Great to have another runner onboard, welcome in!