Oh. My. God.
It's rare that you see a demo game on Newgrounds, and when you do, it never seems to engage players and make them want more. But this is a masterpiece in its own right. Okay, so it's not perfect, but there are no major flaws (and next to no minor flaws either) in this game, which, unlike a lot of games, make it worth the 20 minutes you spend playing it, and in the case of this game, about 3 hours for the full version. Even for a demo game, this is better than a lot of games I play. A game done to its best, and a 5-star rating for you.