Kill the Aliens who have invaded your city, don't let them enter your secret refuge!

One cold winter's night the world is invaded by an Alien race. Alan luckily has found refuge in a building and will have to fight and resist to protect his post !!!

You will be put to the test in dozens of levels, protecting your positions scattered in the building's area.

An arsenal of weapons will be at your disposal to repel the hordes of Aliens and continue in the game, level after level you will have to clear the whole building from the terrible Aliens!