Games Like Alien Insanity

Aliens have invaded Earth and they're not the little green men of the movies. These thing are weird. Mechanical steam-powered shell creatures... Bipedal robots... Flying eyeballs drones... Can this all be real? This game is a 90's retro style game. The aim of each level is simple: Kill all the aliens - then find the exit. But each level has a twist. (Some literally). The story so far... It is the year 2099. Over a hundred years have passed since the Voyager space probe was launched into outer space with its message of peace. Then on Tuesday August 15^th 2089 we got a reply. A formation of seven spaceships each approximately the size of Hawaii descended into our upper atmosphere. Radio broadcasts were beamed to the ships from the leaders of the ten world superpowers. In the days that followed high ranking officials began disappearing apparently due to the alien presence. As a member of the Secret Intelligence Service for the United Nations you were ordered to keep guard on the President of the United Nations. One night a strange wormhole appeared and sucked the President through. Taking no thought for your own life you manage to jump through after her*... (*yes that's right. A woman president. Sounds unlikely right? But this is the year 2099 after all).