A few years back, he did a beta of a game called Four Letter Word... Though that's not the real title: http://distractionware.com/blog/2011/11/the-four-letter-word... The real title is a set of cryptic non-alphabet characters.
It was like an Atari 2600 cartridge from a space alien. It featured 2600-style graphics, a hidden hard-as-nails FPS game, and a buncha hidden 2d content that seems simple at first, but was super intriguing. So crazy non-traditional, and with some obscure mechanics, it was one of my favorite things I've ever played, and he never finished it, sadly. I love cryptic games, and I love simple mechanics taken to extreme conclusions. That's why I adore Terry.