To understand POWDER, you should first understand Roguelikes. "Roguelike" is a term applied to a wide variety of games which share a common inspiration from the game Rogue. A non-exhaustive list of such games would be: ADOM, Nethack, Diablo (I & II), Moria, and Angband. My apologies to the many excellent roguelikes I didn't list. What characterizes these games? The exact specifications are a matter of debate - indeed, I may receive hate mail for including Diablo - but I shall try to write a few:

• Tactical play. The unit of action is based on the individual adventurer. The game is not twitch oriented (like Quake, rewarding reflexes & well trained actions) nor is it strategy oriented (like Civilizations or Warcraft, requiring working on the large picture)
• Based in Hack and Slash. A roguelike isn't primarily about plot development or telling a story. It is about killing things and acquiring treasure.
• Random games. A roguelike is a dungeon crawler where no two games are the same. The maps are different, the items are different, there are no guaranteed win paths.
• Permadeath. You die, that is it. No restoring a savegame. Good roguelikes delete your save game after loading them. This is compensated by the replayability of the game.
• Complex interactions of properties. While the commands for a roguelike are simple, the potential interactions are not. My favourite example is equipping a silver ring as a weapon in order to damage a creature vulnerable to silver, but not one's other weapons.
• Steam rolling monsters. If a critter is in your way, and weak, you shouldn't even notice it is there.