TT Games has just released the PC demo for Lego Batman 2: DC Superheroes. The demo is currently available for download directly on Lego's website and weighs in at a relatively light 799mb.
The demo of Lego Batman 2 should give you a good idea about what the game is about, and it works for all versions of Windows.
As expected, players take on the role of Batman and a variety of other DC characters both within and without the Batman continuity. Lego Batman 2 is the first game in TT Games' Lego series to feature dialogue.
The demo is also available on the Xbox 360 or PlayStation 3 through Xbox Live and PlayStation Network, respectively. The game is out today in the US and is set for release on June 22 in Europe and on June 27 in Australia.