A lot of FUN
Graphics -- Wait, what graphics?
Yes, the graphics are.. disappointing for most people, but that's easily fixed through the use of graphic packs, which are only a web page away on the forums.
Sound -- The music is quite relaxing, but there isn't really any SFX in the game. Again, fixed using mods, specifically Soundsense.
Gameplay -- Now this is where all the cool kids hang out. DF doesn't have any limit or goals, it is - in it's essence - a sandbox game. You can build a fortress spanning 9x9 on the region map, or you can make one big tunnel straight down to Funland. On the other side of the coin though, is Adventure mode, which puts you in control of one lone character with which to brave the wilds.
Interface -- DF has an interface that could only be described using one word. Complicated. It's entirely keyboard-controlled, although some screens support limited mouse interactivity. All the tools at your disposal are accessed using keys, for example, building a mason's is done with [B]uild-[W]orkshop-[M]ason. Confusing at first, but rather intuitive.
Story -- Unfortunately, DF does not have any pre-built story, rather, you forge your own throughout the game.
Price vs. Value -- Now, another reason why this game is so great, is that it's free.
The game is free to download at the Bay12 site, though donations are appreciated.
Conclusion -- This is a MUST to try out. If you haven't played it already, do so now, there'll be lots of Fun!