Wow, sounds awesome. I had never even heard of Hyper Reverthion or Elemental Master.
Electronic Gaming Monthly mentioned Elemental Master would be called "Thunder Force 4" in the U.S., even though that did not happen, it was just Elemental Master.
EGM issue 17 - December 1990
EGM's spin-off Sega magazine Mega Play - issue 2 Jan/Feb 1991
EGM issue 20 March 1991
EGM issue 19 - February 1991