I even turned down a request from the Puzzle Pirates guys to include it as a minigame in their game (that was a mistake), and OmgPop almost paid me to make a version for their website (shortly before they made Draw Something and got bought by Zynga), but I was too busy trying to finish my degree at the time.
I've been tempted to start an open source version to get some help developing it, but I started getting more into board game design lately and I've been programming less and less in my spare time. Kinda hoping I get a reputation in the board game world and then get a board game version of Proximity published (it's an abstract, so it's a harder sell to publishers).
Anyway, I'm glad you enjoyed the game. Hopefully someday I'll put out a newer version of it.
Just imagine if you were playing chess against an opponent and as soon as you made your carefully planned movement the other player immediately made his move and it was your turn again right away. It feels pretty aggressive, doesn't it?
So I gave players the impression of the computer taking time to think by instituting a random delay (within a given range which I tested until it felt right) before it acted, and I think it felt a lot more natural and less aggressive because of that.
If people are curious about the game, it's easy to find and you can play it online.