It's a good game, but demos have no place here. I can understand if you're an indie developer trying to get the word out about your games, but "conning" Newgrounds users into playing a cheap demo is not the way to do it. There are plenty of places you can go to promote a game and try to sell it to a larger audience, Newgrounds is not one of them. Here, it's just perceived as shameless advertising.
It's a shame, too, because I feel this game could have been very enjoyable if you'd given us the full version. If you plan on making another one of these in the future, and I sincerely hope you do, please don't give us half of the game.