Delve Deeper is an excellent game. It's smart, unique, easy on the retro-loving eye and, now that the Treasures and Tunnels DLC has been released, pretty huge too. Fresh off the indie forges of Lunar Giant and costing less than one (rapidly devaluating) dollar, Treasures and Tunnels extends the game with 10 new levels -including the brilliantly named Big Orc Candy Mountains- and 25 brand new relics; that is 50% more Delve Deeper maps, 30% more treasure and absolutely no extra fat. Oh, and apparently each level is custom-tailored to be tackled by different teams of dwarfs, whereas each new relic is designed to influence both new and old maps.
You can download Treasures and Tunnels via Steam; it does obviously require that you own Delve Deeper. As for the people still wondering what Delve Deeper is (besides -as already mentioned- excellent and a game), let me just say it's a turn-based, strategy/RPG affair with lovely pixel-art graphics and board-game influences. Here are a couple DLC piccies to further entice you: