Ufo Killer is one of those tremendously simple action games, without great graphics, but with an idea that makes them really addicitve and entertaining for a while.
The aim is simple: you must destroy, from your shooter perspective, the largest number of UFOs that are attacking the Earth. Logically, the more you kill, the higher your score and the less damage done in their invasion of our planet. So, you need all your skill and judgement shooting as accurately as possible to destroy as many as possible.
To work correctly you need to previously install
DirectX 5.0 or later.