Aside from getting the high-definition treatment, what are the differences between the two? New translation, new voice acting, audio remastered, extra goodies, the deluxe content from the original comes with this release, etc etc etc?

When I try to purchase the bundle pack for its discount, having already owned the original Harmonia, selecting "Continue to Payment" at checkout redirects me to the Steam homepage. Attempting a transaction with just the HD Edition works fine.