Metal Slug 3 by Sintax – Unlicensed GBC Action Platformer, Fio as Hero | Game Boy

Sintax looked at all of that and built their own version for Game Boy Color, calling it Metal Slug: Yue Nan Zhan Yi 3 (越南戰役3). It arrived around 2002–2003, and it was functional enough that Sintax reused its engine for at least two more unlicensed GBC games — their Metroid bootleg and their James Bond title. That's the quiet legacy of this cartridge: it wasn't just a one-off knockoff, it was the Custom cartridge, plug and play. Compatible: GBC, GBA, GBA SP.