Caravel has released the first three episodes of "King Dugan's Dungeon Lite", a flash version of the original DROD game. Contrary to the name, it is all but identical to the 2.0 release with improved graphics, voice acting and just as many puzzles as before.
In addition to all the monster hacking puzzles you'll remember from the original, each set features a bevy of optional achievements to earn. Unlike your typical flash game achievements to 'do thing x times', most of these are clever, optional puzzles that tease you to beat levels without using potions, without turning your sword, or without stepping off the path.
Every episode also features a bonus mastery area with extra puzzles to solve if you can master the initial content.
While these episodes only take you up to the halfway point of the original game, further episodes are in the works to take you all the way to the final level.
This is pretty definitively the game to play if you've never played DROD before and are looking to start, since it marks the first of Beethro's adventures and will ease you effectively into the puzzle features. No download means you're only a click away. I very strongly recommend this game if you like turn based puzzles!