The basis is an unfermented but hopped Guinness wort extract shipped from Dublin, which is added to local ingredients and brewed locally. The abv may vary.
You want bitter? You got it! Very malty with a strong roast barley flavour. Black as pitch and so thick you could just about eat it with a spoon. An excellent stout.
Jamaica Stout is a strong Foreign-Style Stout brewed in Kingston, Jamaica (naturally enough) by Big City Brewing.