div.enemyShip {
	position: absolute;
	overflow: hidden;
	height: 40px;
	width: 40px;
	left: 0px;
	top: -40px;
	background-size: contain;
}
div.enemyShip.standard {
	background-image: url(../gfx/enemy-ship.png);
}
div.enemyShip.boss {
	background-image: url(../gfx/enemy-boss.png);
}
div.enemyShip.ufo {
	width: 80px;
	height: 38px;
	background-image: url(../gfx/enemy-ufo.png);
}
div.enemyBomb {
	position: absolute;
	overflow: hidden;
	height: 16px;
	width: 10px;
	left: 0px;
	top: -16px;
	background-image: url(../gfx/enemy-bomb.png);
}