Wonder Boy in Monster Land, in its "Japan New Ver." iteration, features updated elements from its original arcade release by Sega. The MC-8123 designation hints at a possible internal Sega identifier. This version likely incorporated improvements over earlier releases. The gameplay involves traversing various side-scrolling levels, engaging in combat, and collecting items. Sega developed and published the original arcade versions.

Wonder Boy in Monster Land (Japan New Ver., MC-8123, 317-0043)

Wonder Boy III - Monster Lair (set 6, World, System 16B, 8751 317-0098)