This reminds me of how Oscar Toledo disassembled Video Chess, which ran in just 128 bytes of memory:

https://news.ycombinator.com/item?id=36431917

It uses lower 4 bits of 64 bytes to store the board positions (upper 4 bits is used to store other data). 64 nibbles is 32 bytes, not too far off from the 26 bytes here.