Hi, Stewie! You're right, here are only three levels available - but we want to know, whether you like the game or not. If we see, that the game is interesting to play and rated high by its players, we definitely build new levels for you. If not, well, we have to concentrate on making something else - this war between cows and vikings will be stopped.
Since this is a demo version, the other levels will be added after we'll see that players have good level of interest for the existing ones. Your comment give us some hope.