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What happens when you take the classic Astroids game, remove the asteroids, add 50 enemy ships, and independantly simulate the trajectory of each particle of ammunition? You get Astroflug – a rather addictive though simple arcade game. There are four levels of difficulty: beginner, intermediate, advanced, and epic. Windows and Linux binaries and sources can be gotten here. It is written using SDL, so you will need SDL.dll in C:\WINDOWS\SYSTEM32\ or just in the same directory as astroflug.exe on Windows or install the libSDL12 and libSDL12-dev packages on your favorite Linux flavor.
Perhaps the coolest feature of Astroflug is that for each particle or enemy ship in the game a force is calculated and applied with respect to every other particle. That is, everything interacts with each other in a physical way. The result is very smooth-feeling immersive gameplay.
When you start to get pwned you can use a bomb blast that fires all your ammo at once in every direction. It is fun to watch how the shock-wave reacts to and wraps around the enemy ships.