Crystals of Niberium

Planet Niberium turned out to be rich in rare precious crystal. Space Corporation Sigma decided to extract these crystals. The extraction was carried out by NKX-627 Robot series. However, soon the Corporation Sigma discovered that they were not the only ones who were interested in the crystals. The Corporation Sigma goal is to collect all the crystals and take them out.. There are 20 levels in the game.