OK, I've been randomly searching through youtube and found this video,

http://www.youtube.com/watch?v=Usg6L_Jk9y4&feature=related

amongst others, and thought the game looked pretty good, but I don't know which game to buy. Are the stories linked in the sequels, or could I start anywhere in the series? Is there any particular difference in control quality from sequel to sequel, I'd rather not have a case of Forbidden Siren/Forbidden Siren 2 playing the game.