The game's demo has now been made available in the "download" section.
It is a 26 megabytes download and it offers a playable version of the first ten levels in the game.
These are the introductory levels and although easier than the rest of the game, are a good introduction to the base mechanics of the gameplay.
They should give a good idea of the game's content and what type of gameplay to expect.
The demo also includes three cinematics.
Remember that you can interrupt the cinematics at anytime with the 'ESC' button.