Tetris only had the lowest because the cartridge contains just a ROM chip and doesn't have RAM or memory bank controller chips as other cartridges have. I'm su

Tetris only had the lowest because the cartridge contains just a ROM chip and doesn't have RAM or memory bank controller chips as other cartridges have. I'm sure the halt instruction does reduce CPU power but it isn't that significant compared to the overall power of the cartridge and other peripherals.