bugackt gave me a couple of links to Japanese blog entries about Bounty Killer to gather some more information and, well, I tried. There you are.
Translated by
akogare for
gackt_army. Taking out only allowed with credit! Please comment before and state where it is going to be reposted.The story revolves around two bounty hunters who have to fight monsters like Dracula and werewolves and seal them into cards. The names of the characters are Jessica Birkins/Barkins and Gide Bellecourt (thanks to
bugackt again who found the correct romanization for the last name!)
(taken from
this blog)
( Picture of the actual machine and price )There's a nationwide limit to 20,000 of these machines.
Next, there's a couple of goods related to Bounty Killer, namely a pamphlet, a lighter and a set of trump cards.

Picture taken from
this blog.
edit: I just randomly checked Yahoo!Japan Auctions and saw that there's also a DVD.
( more pictures of the goods )( some info on the game itself )( two more pictures of Gackt and the female )You can watch two videos of the machine being used (one with the female character and one with Gackt)
here.
Pretty much all writers (they played a demo version) said that the machine is fun and as expected, the sound is very good *laughs* as well as the graphics.
One blog said that they think even Gackt fans who are beginners (with slot machines) can play it without worries.