Cattle Admission Challenge

The year is 2087, the Technotron rules the world. All biological creatures have been exiled to the wasteland. In a remote section of the Grasslandia border Sentry 49-42 must protect the zone from bovine scourge! The sacred grass must be protected. All moo cows must be exterminated.How to play:Prevent the cows from crossing the border.Controls:
Fire cannon: Left-click
Zoom: Right-click
Switch Fire Mode: E
Quit: Menu
Toggle Music: M