Update []:
City Connection's next Saturn Tribute has been revealed as Steam-Heart’s & Advanced Variable Geo (thanks, Gematsu). Both are based on the Saturn versions of each game.
"This is a collection including Steam-Heart’s, a classic science-fiction shoot ’em up game known for its cute visuals, and Advanced Variable Geo, a fighting game also popular in the worlds of anime and comics," says City Connection. "In addition to adjustments typical of Saturn Tribute ports, the collection also features a variety of options, such as “Save & Load” and “Rewind” functions, to support both long-time fans and new players alike."
Giga's vertically-scrolling shmup Steam Heart's (yes, the apostrophe is deliberate) is infamous for its adult content. It originally launched on PC-98 in 1994 and is packed with erotic cutscenes; when it was ported to the PC Engine (1996) and Saturn (1998), the saucy content was drastically scaled back, with the Saturn port being a lot tamer than the PC-98 original. Unfortunately, Steam Heart's is more famous for its adult tone than its overall quality.
Giga also released Advanced Variable Geo on Saturn in 1997, and again, this is based on a series which began life on the PC-98 home computer. Like Steam Heart's, the Saturn port scales back the erotic nature of the cutscenes.
The double-pack is coming to PS5, PS4, Xbox One, Switch and Steam and will be released on May 29th in Japan. The PS5 and Switch versions will be getting physical versions.