Since 1983, the record for the smallest game of (computer) chess in the world belonged to 1K ZX Chess, at 672 bytes, a game so small you could print its code in a magazine article. It took nearly 32 years, but that record has now been broken.
BootChess may not be pretty, but this isn't an art contest. At 487 bytes, its significantly smaller than 1K ZX, to the point where folks are having trouble seeing any way the code can be trimmed.
But then, they probably said that back in 1983.