Why were some Famicom games on floppy disks?

Start with the chip shortage. Cartridges were built from semiconductor memory that was scarce and costly in mid-1980s Japan, and it showed in the shops: cartridge games sold for 5,000 to 7,000 yen, in limited runs that sold out. A Disk Card was stamped plastic and magnetic film. Disk games sold under 3,000 yen, could be manufactured quickly, and in 1986 a disk's roughly 112 kilobytes was more room than most cartridges offered.

Rewritability changed the games themselves. A disk could be written to, so progress could be saved onto the disk instead of transcribed as a password. It also changed the business: with Disk Writer kiosks, Nintendo could sell the same physical disk again with a different game on it, and the format added an extra sound channel that composers used immediately.

The same openness ended it. Media that any kiosk could rewrite was media that anyone could copy, and piracy spread; margins on disks were thin, retailers cooled on the bulky kiosks, and by 1989 larger, cheaper cartridges had erased the disk's advantages. Nintendo let the format go, and the Disk System became a Japan-only chapter: nearly four million drives, and a generation of games that began life on floppy disks.