Nintendo Entertainment System cartridge variations

Compared to the Family Computer, Nintendo had greater control over cartridge manufacturing for the Nintendo Entertainment System outside of Japan. Third parties were required to buy Nintendo manufactured cartridges, PCBs, and if needed, custom mapper chips. While there were some exceptions, Nintendo continued to regulate the manufacturing of cartridge shells. This led to a lack of variety, making many NES cartridges look alike compared to Famicom cartridges. Despite this, some companies like Tengen produced their own unlicensed cartridges, deviating from Nintendo's standard cartridges.