It took a while (the whole game really) to understand how to play this. It's an interesting game, somewhat complex, with cards that are little tributes to xkcd. It seems you're quite a fan of the comic.
I do agree with @Rainbow Serpent Labs's ideas: a tutorial and multiplayer would be great (perhaps after the jam is over?). Sound and music would really make this game, as it's already quite well done, but needs more audial feedback and awesome tunes.
I got my butt kicked by the AI, but the screen still said "You Won" (even though it clearly displayed the scores [Me: -3, AI: 19]). Also, the bun's words on the ending screen are some kind of haiku (syllables go 4-5-4)--was that intentional? It's nice. :) Though I would have liked a restart button.
This game is pretty cool--a really neat card game that's also a tribute to xkcd. Great work! :)