Sheep in Space is a horizontally scrolling shoot'em up by the legendary Jeff Minter.
In this game you pilot a sheep-shaped space-ship called a "sheepoid" inside a space station. Your ship flies in between two landscapes at the top and bottom of the screen. While your ship is towards the middle of the screen your shots fire straight. If you are closer to the top or bottom landscapes then your shots curve up or down as if attracted by gravity.
In each level there are a number of enemies which need to be destroyed. Your nearest target to the left or right is shown by a proximity sensor at the bottom of the screen.
As you fly, your sheepoid loses energy, described as your Stomach state. This runs through the following descriptions: Bloated, Replete, Full, Adequate, Not Bad, Peckish, Rumbling, Famished, Dire.
If you run out of energy, you die and lose a life. To replenish energy there are pastures at which you can stop and graze. Your stomach state steadily increases, but if you allow it to go above "Bloated", your sheepoid explodes!
Your sheepoid also has a number of shields to protect against running in to enemy craft. When all shields are lost, a further hit will also lose a life.
The enemies are heading towards a series of reactors. If they reach their target then the station explodes, however you can continue to fight in space (but without the ability to recharge your energy).