Oh, the Japanese-only version. Interesting. That is the only version I've never played, haha
2HC has a "turbo mode" that makes the game run about 20% faster. It's challenging to consistently land the izuna holds in that mode. Everything is so quick, you have to be on your toes!
If you're playing on 2HC, try playing in Turbo mode.
Izunas on crack, haha