This is interesting for its definition of "simple". While it is built from only simple building blocks, it is written in a way that I find very hard to read. It's easy to follow with the comments, but without them, would you be able to quickly find out what the code does and whether it is correct?
I think actually using abstractions (like functions, arrays (which are used in v2)) would make this even simpler, or at least easier to understand. Nobody would argue that a Tic Tac Toe game made only from NAND gates would be simple (to make or to understand).