I am not really into the whole card game thing. I just don't think it's quite appropriate for a flash game. I will however, admit that there was nothing really wrong with this. I do wish it had sound. I thought it would be a conquering game. With the title, I thought it would have more action.
I also think you should have shown the action on screen. It would be nice to see the creatures actually fight each other. Well, I don't know if it works that way. At least it was easy to understand. I still couldn't get into it.