I'm learning the any% run on an emulator, and I'd just like to make sure that ds/gba isn't faster.
Emulator is faster than any original console, hence it's banned for top times. Also make sure not to use the banned emulator VBA-M (Take VBA or VBA-RR instead)
Every Kirby game accepts emulator runs (Except of Super Star Ultra). Only a World Record doesn't get accepted in most of them.
As already mentioned, just aviod using any banned emulators like VBA-M and you'll be fine. SRL provides a list of all recommend emulators for all consoles:
I was searching a kirby game for speedrun and I'm interested in Nightmare in Dream Land or Amazing Mirror so, talking about emulators would be allow use bizhawk lastest version with mGBA core? well, is more accurate than vba and almost same than console(not totally sure) for some games.
It doesn't matter at all which emulator you use as long as it's not the banned VBA-M. So mGBA should be fine for runs, even though they are not being treated differently because they are slightly more accurate than VBA.
It's still faster than console, so it gets marked as an emulator run just like VBA. It's up to you which one you prefer after all
JP is only faster in Super Star, Super Star Ultra and Amazing Mirror. In Nightmare in Dreamland it doesn't matter at all which version you run on