Shadowrun: Dragonfall was originally DLC for Shadowrun Returns, but got turned into an expand-alone game. The game mechanics are mostly identical between the two (from what I noticed). However, Returns is set in Seattle, but Dragonfall is set in Berlin. The two have zero story continuity, aside from two characters appearing in both (not even your own), and they don't refer to anything in Seattle.
That said, they are similar in design, and most of what I write here applies to Returns. The largest differences are that guns automatically reload after combat (I think), and characters revive when you make it back from a mission. The last game had a permadeath in this situation. I have the director's cut version (the only one available right now?), which includes the soundtrack to this and Returns. I'll be listening to it for a while.
I enjoyed the story, and the characters in it. Like the last game, Dragonfall has its share of plot twists, and very unforeseen ones (my foresight is very poor). The gripping backgrounds of your team members unfold if you pry at them correctly over time. The team's shaman has an idol (as they all do): the dragonslayer. As in, the guy we're supposed to be looking for? Can you ask your god where we can find him? (It doesn't work like that? What a ripoff!)
The setting is does its job. It's not the urban nocturnal rainy vibe that the last one kept giving you. Instead, Berlin has turned into an anarchist experiment. Neighborhoods have been fenced off from one another, in an attempt to isolate the gangs into demarcated territories. Somehow, the subway still works, and functions as a teleporter to get around into new areas. Megacorporations, their security, and their contracted security form the only legit governing structures.
As an aside, I've been to Berlin. I opened Google Maps, tried to find the places where the game happens, and found about half. I'm very sure that I've been in the gang-run train station (down the street from one of the places I stayed). As for the others: I might have been through one of those neighborhoods.
Enemies are decently smart (except when they run away from your tank, then return to the same spot), and can be annoying at times. When you clump your team members close together, enemies will spam grenades. Some enemies have nothing but flashbangs, which decrease the number of actions they can do in the next turn. Get too many, and they won't be able to do a thing until the next round (like move away)! Early on in Returns, that action number went from 2 to 3. I wondered how that happened, and searched in vain for how get it. (Was it a stat? Equipment upgrade?) I did some research, and it goes up whenever the story tells you. It eventually does in Dragonfall, as things start wrapping up.
Sometimes you will be stuck in combat mode for what seems to be forever, only to figure out that the gargoyle statues come alive when you get close. Other times, enemies lurk a little bit off-screen, or there's a countdown to when enemy reinforcements arrive, and you need to hurry up.
The game has its technical flaws. The game will stop responding to input sometimes for who knows what reason, but it usually clears up in 10 seconds or so. If not, I've had to exit and load a game because of it. The game has some auto save checkpoints, in addition to before and after missions, but you are free to save at any time outside combat and dialog.
The interface has been reworked. It works better on larger monitors (as opposed to phones and tablets). it uses the extra space to have a semi-permanent inventory of a character's equipment or spells. However, the journal and stats menus are the same, and I noticed no changes there.
The side missions let me down the most. You need to raise an insane amount of money for information during the middle part of the story, and this is side mission time. There are two other factions that contact you. One started with a very cool infiltration mission (a "test"), that goes to hell fast. But later on, both contact you during major missions and ask you to do side work. I expected them to give me their own missions, and to not ask for favors on others. (I see you're at this place. Can you steal their project data? Can you tell this guy something?) One had the guts to ask you give them the mission objective instead of the guy you contracted with! Fortunately, an awesome team member is vocal about sticking to the objectives, and will remind you if it looks like you might slip up.
My favorite kind of mission is where you don't shoot everything that moves (or at least, not right away). You usually get in by disguising yourself as a wage slave in one of these megacorporation's offices. In one mission, I was able to disguise myself as a security contractor, and slip past people with the "hostiles sabotaged the power, boss wants a full perimeter sweep" excuse. Suckers!
The graphics and art style are the same as Returns. Part of the charm for me is that it looks a lot like old Blizzard games: top down isometric, dark gritty feeling, and fog of war. If I relax enough, I can become that kid playing StarCraft again, entranced by what's lurking a bit beyond visual range.
If you liked Shadowrun Returns, you will LOVE Shadowrun: Dragonfall. It has more of the same gameplay, has a different setting, with different characters, and an even better story. There was something about an actual dragon, too, but I forgot. Like the last one, it will run on a calculator of a computer. (Yes, it will run fine on integrated graphics.)