Double Dungeons is a role playing video game developed and published by NCS for the TurboGrafx-16 in 1989 in Japan, and in 1990 in North America. It was released for the European Virtual Console on Nintendo's Wii console on March 9, 2007, and on the North American Virtual Console March 12, 2007.
In the game, players make their way through 22 dungeons, earning gold and experience by killing enemies. This gold can be used to buy items and weapons at a shop, or rest at an inn, while the experience points helps to raise the player's level.
Source: Wikipedia, "Double Dungeons", available under the CC-BY-SA License.