I really liked this! The old-school graphics and sound compounded by the classic-style gameplay and the enjoyment of just running around eating the innocent was enough to keep me playing through all the levels. It's reminiscent of Strong Bad's "Trogdor the Burninator" game. I wish there had been a bit more challenge... if you just go around mashing space, you eat everyone, including the cops, and even if you do it right in front of them the cops don't care. It was fun to transform, but relatively meaningless considering you can easily win the game without ever doing it once, and even if you are transformed the cops only bother you if you are transformed AND eating people.
I'd play it for hours if it were more challenging, but regardless of that, I still played it all the way through.