It seems there is a glitch! When I boot up the game and press "Play", the 'start up' sound for the level happens, but the actual flash itself stops and I am left with a black screen. Even right at this moment I can hear the music but can neither see anything nor interact with anything.
I am playing on Google Chrome, if that assists you.
Still, 2.5 stars because, despite the glitch, I remember playing this game in the past and finding it incredible, so bonus stars for nostalgia.