It looks like this is missing an additional composition credit: Yasuhiko Takashiba
From the staff roll:
picture from MAMEND
On the original 1993 OST
, they only received a "special thanks":
But they were credited as one of three composers on the Arcade Disc In JALECO -VARIETY-
(Soldam is the third game on CD 3)
It's possible that the entry in the booklet might explain things, but I can't read Japanese...
(all scans from VGMdb)
Later this month, there will be an all Soldam album
, featuring music from the original, the GB conversion, an unreleased Famicom conversion and the new Switch game Soldam: Bloom Declaration
. Maybe the booklet from that will clear things up a bit.
, who is behind both the Jaleco compilation album and the game, owns the rights to Jaleco's IPs since 2013)