Overall, Sinking Island is not a bad game at all and will appeal to those who are more interested in slowing things down a little and doing some thinking about what you are playing. GameShout would consider that this is more of a thinking-person's game allowing the player to puzzle out clues and evidence and a lot of dialog. It is not a game that will appeal to those looking for fast-paced action. And so for what it is, it will have an appeal to a limited audience.
But don't discard it too fast because it can be very relaxing to just slow things down a little and exercise your brain. Most can use that afterall.