Picked this up on a lark.
Conceptually, the label of "DF meets Terraria" is actually close to what you'll get. The game relies on the player using their team of dwarves to extract, process and place resources and items to build a fortress in the 2d-SideView style of Terraria.
The game plays smoothly, with very few issues and no crashing. It's a very casual atmosphere, animations are cute and appealing, and things work about like you'd imagine of you've ever played Terraria (esp. regarding foreground/background and housing). There's a bit of complexity, but by no means is this equivalent to DF - the procedural generation is limited to world and creature spawns, and the tech tree is much like Terraria or Minecraft: iron -> steel -> etc.
Combat is mostly a "throw your horde in at the right moment" affair, with some traps and defenses to help them out. You tag enemies, and your dwarves charge in to attack them (fighting on their own if they have an untagged enemy close by). You can take over a single dwarf directly, whether to force them out of their current action or to directly impact combat, but I'll admit I haven't found much use for it yet personally, aside from nudging the infrequent pathfinding freak-outs.
The player is given access to some direct influence in the form of magic spells they can apply, but the mana is slow to regenerate (at least, to start) and limited so as to force careful rationing early. These spells range from temporary portals (teleport from stockpile to resources and back, with multiple destination locations at once possible) to lights or forests on-demand and also some combat spells (like the ubiquitous "fireball"). Consumption rates are often greater than they initially appear; the fireball often takes a couple of applications to kill something (but is great for disrupting a stack of skeletons forming up a 'human pyramid' while trying to reach a floating palace) and the portal's time limit decreases more rapidly when it's actually used, making the 3:00 duration limit less relevant than the number of resources in proximity! None so far has seemed imbalanced, and all have had some application, especially the portal.
There are nightly spawns (zombies and skeletons), periodic goblin raiding camps will form and every ~45minutes a larger (and increasingly dangerous) wave of undead foes will swarm in - this can include giant skeletons or "beholder" type mobs that are more dangerous than the average foe. Belowground, there are ant nests and spiders, as well as spirits of darkness and tunneling worm larvae lurking below ground - and that's just the first map. While there's a good variety of foes, once you've seen what the first world has to offer, you won't be able to expect more out of that same map. (No idea yet if the second map is identical on enemy types!) Unlike in DF, there don't seem to be any real "game breaking" strategies (though I haven't tried the Minecraft "sand wall" defense yet, so caveat emptor). You can use the portal to teleport your dwarves out of the shelter to somewhere safe underground if you think you'll be overrun, but the undead foes will smash your walls and doors to wreck your house while you're gone, and goblins can steal your items and resources for themselves!
The random worlds and procedural randomness can make the combat sometimes feel a little unbalanced (be ready to run if needed!) and while the enormous tech tree is certainly detailed, it's also a bit of a grind to "level up" in some places in order to get more dwarves and access to the higher tech, as this involves making items which provide diminishing returns if you use only one item type to gain skill, which forces you to make a little of everything and need a little of all the resources. Why grind? Well, deep in the world is the portal room, which must be cleared and repaired in order to get access to the next map. As you might imagine, its guards won't go down to stone knives and wooden clubs. You'll want ranged weapons and mages, as well as well-armored tanks, if you plan to go toe to toe with the guardian to "win" a map - and that means new tech progression is required.
I've made a couple of half-hearted attempts at building an "entry proof" fortress, but the skeletons can build bone bridges, form 'human pyramids', climb ladders or scaffolding and smash walls (like the proposed DF digging!) and doors, so while you may be able to whittle down their numbers by making them play human pyramid, there doesn't seem to be a way to 100% keep them out... yet. In this respect it's far better balanced than the much less enjoyable "Game of Dwarves" I tried previously, which was far far too easy to play once you broke the economy. (Gnomoria is on my list too, but I haven't gotten there.. yet.)
It's a casual game, but if you're looking for something you can play to scratch your itch while DF and its utilities are locked in a battle to see if LNP will beat Toady to the next release, it might be worth a look, provided you're not expecting it to replace Dwarf Fortress. It's a casual game with good difficulty, not a roguelike.
I'd give it a 7.5 or 8 out of 10 - if you don't mind the 2d graphics, it's an enjoyable little romp. Snag it on sale and don't set your expectations too highly, and you'll be fine.