Your farm has come under attack from the most unnatural collection of enemies possible: wolves, ritualistic cultists and the United States military.
Its not obvious what exactly has prompted such a conflict, but all of your enemies seem to be after the same thing: your livestock or more specifically
Use keys 1,2,3,4 to switch between weapons quickly.
Research new upgrades and tech.
Protect your sheep at all costs.
More instructions available in-game.