The game was made in (I believe) Gamemaker, so it doesn't offer any joystick support. I compensated by downloading Joy2Key (which I highly recommend), and I played through it with no problems.
I only encountered one bug. When the ferryman rows you across the lake, DO NOT crouch while the screen transitions. I got stuck inside his ship, with no way to move or die. I had to reset and do an entire mansion over (which now can get tough).
Off topic. Not having joystick support has nothing to do with it being a GameMaker game. Joy2key is a great way to augment those games that don't implement joystick support.
On topic. I really need to try this beastie out. I've heard good things about it in it's development threads over in the Fan Stuff section.