Wow, I wanted desperatly buy the game but now seeing this I will probably skip it until it's super cheap in a sale.
The problem with many "DF-ish games is probably that they misjudge the challenge they take. DF is one of the biggest games to date of while being minimalistiv as possible (no mouse control, ASCII graphics). The game focuses more on a deep code that organizes all the stuff that happens. A mass of calculators.
The nearest thing I could find was Gnomoria which is done by a single person. It's like a "basic DF2 without all the complex stuff like temper thrantrums and special needs. However you could do all the basic stuff from DF. Dig tunnels, create farms, workshops and other stuff, produce goods, trade with other nations and repel invading enemy forces. there are howver no mystic beasts or other boss stuff. the nearest thing to a boss are "spiders" who are endgame enemies encountered underground.
Gnomira is however very simple, there are not many different ore types and there are less food types. You gnomes (instead of dwarves) need only food and drinks. You CAN boost their happiness with better furniture but this has only a little affect in them. Gnomes will always obey and the wirst thing that can happen is that they will occasionaly because they are too tired/unhappy. Gnomes do not reproduce, you can only get immigrants when the worth of your kingdom is high and you have free spare rooms.
There are only some simple mechanics so there won't be a fancy trap building system, however some players got wuite creative with the tools they got so it depends.
And unlike DF you will come eventually to an end. While there is no end goal at some point at the game you will gave seen everything that there is to discover. Every item created, every building constructed, every enemy type defeated and so on. And after you've seen everything you can either play until you are bored or until your kingdom is destroyed. Also you are stuck at one place. Unlike DF there is no giant world that you can discover. You have one world created that you can horizontally scout in 5 minutes (depending on your world size), vertically might or might not be an end (O've never reached an end but that can kust mean I've never digged deep enough).
For me Gnomoria is the answer to everyone who finds DF too complex, too unappealing because of it's layout. Gnomoria features a pixel style with an easy understandable GUI where you don't have to pick ypurself through 5 menus until you've reached your destiny. The manual is however outdated...
Aside from Gnomoria I can really advise the german game "Wiggles" in some countries it's however called "Diggles" as far as I know. It is more or less the "ancestor" of Dwarf Fortress of you want to say it like this. Created in 2001 it is already very old and it's graphics are outdatted but it still works perfectly on a Win 7 PC. The game is like a 2.5D version of Dwarf Fortress. Unlike DF and Gnomoria you look at the side of the game, not from the top, sou you see the different layers at once (which is quite clever because you don't have to scroll yourself through multiple layers to find what you've searched for).
You play a small clan of dwarves called the "Wiggles" (or Diggles in other countries) that are chosen to find the hell dog Fenrir that run away from the god Odin.
Unlike DF it has a campaign mode where you have to fulfill several objectives to win the game. it has also a free mode for people who don't want a specific goal. The dwarfs have their own feelings and needs, they need food, sleep, free time and also sex. The game is held in a very cartoonish and comedically way, so it is not a full fleshed fantasy game that takes everything seriously. Instead the game gets quite hilarious at some points for example the "Peacers" who are "totally not consuming drugs and instead do a smoke sacrifice for Odin. That wouldn't be possible anyway because of the age rating".
In order to make your dwarves happy ypu have to collect resources. The most reliable resource are mushrooms who are used for food and for constructions (they replace wood). Dwarves collect experience when they do specific tasks, chopping mushrooms or digging tunnels. When they have enough experience in a specific stat they might research a new project. New workshops, furniture, defenses or even weapons and meals are possible. Later you can also create potions or spells, so there is quite some varity in the game. You also have to defend your home from incoming monsters or rival dwarves. You can build traps, forge weapons or just dig yourself in an unreachable place and hope that the only door to your fortress will hold.
When dwarves are happy enough they will reproduce. Baby Dwarves will get some of the stats of their parents and also get a higher stat cap, so they CAN outclass their parents. This makes breeding a very important aspect because you can only get powerful dwarves if you have a lot of offspring.
The game is a lot of fun and for me it's like a sideview version of DF. While not totally as compley and deep it has a lot of varity and all the basic features of Df including the MASSIVE generated world that you can explore. The developers even wanted to create the world four times bigger as it currently is but then they noticed it was too big so they divided it into four different parts. The world (except sandbox) is semi-randomly generated. It has a different layout everytime you start the campaign but some basic structures, tunnels and layouts are always in there because they are needed for the story.
So, if you are searching for a good (and quite cheap game) that is like DF without being, well, DF, you should check it out. No space theme here however :O
The english wikipedia site to wiggles/diggles:
http://en.wikipedia.org/wiki/Diggles:_The_Myth_of_Fenris
