The current AI literally took ~15 minutes to write. I am going to go back and improve it slightly, but not spend too much time on it, mostly just fix some of the incredibly stupid behavior. Practice mode is mostly for allowing players to become more familiar with the game and cards, and is not supposed to be a very challenging experience.
The latest deploy caused some Flash Security errors with some Flash 9 games. This should be resolved now, and the green dot should now be showing up in chat, and the API should be functional for this game once again!
Definitely very professionally done. As others have said, it would be nice if when you finished a 'level' all the enemies were cleared off the screen, as it is frustrating to lose control and then have a bomb hit shortly after. I think the machine you are playing on makes a great difference in the playability of this game. I couldn't finish the challenge for the life of me on my laptop, but when I got home and tried on my much more powerful PC, I got it in a single try easily, and the game was much less frustrating. The difference was so huge, in fact, that I had to change my rating. It might be a good idea to let the user change the quality (unless you're already doing this and I missed it). Other than those things, nice game, nice artwork, and nice music.