Lucius refers to the Bat Gadget difficulty. The Gadgets are collected via the mini playfield until you get all of them to collect Lucius.

I bought a BDK NIB back in 2010. Fun game. I kept it for about 3 years.

One correction, If you get the 3x super skill on a shot and then get the shot multiplier with the green x, that shot becomes 6X. I used to call that "getting all sixed up"! 6x super jackpots are a good way to blow this game up. I'm also a little skeptical of Billion point games. I owned it for several years and my best was only in the 300-400M range.