My entry for Ludum Dare #27, theme is "10 seconds." The game is my take on 2D side-view defense games, similar to things like Defend Your Castle. The theme fits in because each wave of enemies lasts 10 seconds, within a day/night cycle of 10 seconds each. There is a minimalist story around it with and a basic drum/bass tune to go in the background that I hope sort-of fits.
It's written in MonoGame using C#, using Visual Studio 2010 Express Edition as the main IDE for Windows and MonoDevelop for port to Linux. Beyond things included, it requires OpenAL installed to run.