Soulstar was a Mega-CD game created by Core Design, and after its release, two seperate conversions were planned. One was a port to the Jaguar CD, under the same name, whereas the other was an updated version for the 32X, under the name Soulstar X. In the end, neither of them were released.
The 32X update was previewed in Sega Power’s August 1995 issue, but some of the screenshots provided are a bit suspect; At least one of them is identical to a screenshot used on Wikipedia (at the time of writing) to demonstrate the unreleased Jaguar version… Did Sega Power simply get screenshots from the Jaguar CD version due to a lack of available 32X screens? It’s difficult to say, but the preview does confirm a few things about the 32X update, specifically the addition of multiplayer, and a faster game overall. The game looks slightly better than the Mega-CD original.
A playable beta of Soulstar X 32X was leaked by the Sega Saturno Community in February 2010.
Thanks to Adam for the contribution and to Rod_Wod for the scans!