On Bluesky @vgdensetsuさんのイラストまとめ

The first episode of the Shining Force III trilogy turns 25 today! The Premium Disc, released a year later, has become famous over the years for its development diary written by the game's director, Yasuhiro Taguchi:
https://t.co/OBO93Z0UIi
Cover art by Shin Yamanouchi / 山内真:

Pencil versions of the illustrations drawn by Eric Powell (The Goon) for the Contra Vinyl soundtrack.
https://t.co/kt43KoXKVL

An ad for Super Mario 64 illustrated by Steve Peringer:

TMNT Turtles in Time (Japanese version) + Hyperstone Heist (European version) cover art by Steve Lavigne, presumably inked by Ryan Brown:
https://t.co/gvWhH7WhnU

Judy Totoya / Yasushi Yamaguchi have also done cover art for non-Sonic related games, starting with Bomber Raid, the latest Mark III game released in Japan. Other games followed, such as Hanagumi Taisen Columns 2 and Fushigi no Umi no Nadia: Inherit the Blue Water.

Judy Totoya mentioned in a conversation on Twitter that he did the cover illustrations for the following games after leaving Sega:
G Sonic, AKA Sonic Blast (Game Gear - 1996)
Sonic CD (PC - 1996)
Sonic - The Screen Saver (PC - 1996)
Sonic & Knuckles Collection (PC - 1997)

The same goes for Sky Chase Zone, Act 2.

I guess it was Judy Totoya who drew those other Sonic 2 concept arts. He pretty much acted as art director on the game.