Treasure Hunter is basically an underwater crane game that puts you in control of what looks like the step child of the Incredibles family. You don't do that much in this game except press the screen when you want the claw to drop. After that it's mostly just a waiting game.
There are two version of this app, and it's highly recommended that you use the trial version first. The game isn't that complex and really just requires you to tap the screen anywhere when you want the claw to drop. The claw rotates from left to right at a set speed and you've just got to calculate exactly when it needs to be stopped to get your prize.
The prizes are either giant rocks or gold pieces. The bigger the piece, the longer it takes to haul in. And considering each level has a timer, you do have to have some skill at stopping the claw just where it needs to go. While not nearly as fun, this has more in common with that lightning arcade game where you have to stop the light right in front of you.
It's confusing as to why the developers of Treasure Hunter decided not to make the game take advantage of the accelerometer. Think about how great it would be if you could tilt the device to try and get it to pick up the pieces you wanted instead. Unfortunately, that's not this game. Try the trial, but you won't be pleased.