The Roller Foot is one of the feet available to Steve. Its in-game description reads : "Foot that lets you glide along like on roller skates." Basically, the Roller Foot makes Steve roller-skating in floor levels, just like people do with them in real life. In Dark Cloud 2, the Roller Foot is much faster than the Iron Leg and its variants, so you may want to buy or invent it as soon as possible. With it installed on Steve, you'll be able to beat your first Time Attack medals, providing you can easily kill every monsters and navigating through the map without getting lost.