This is part 3 of my installment on the changes between 2004 and 2012 in various states. In Part 1, I examined Virginia, North Carolina, and Colorado, while in Part 2 I looked at Georgia and Florida.
Now here is Part 3. It's a bit different. There are more states, but none of them are probably quite as exciting as new swing states Colorado, North Carolina, and Virginia, classic swing state Florida, or potential swing state Georgia.
I'll begin with two "twin states," Kansas and Nebraska. Really, the only difference is that Kansas has a few more people and Nebraska has a more competitive congressional district. But other than that, they're as similar as two states can be, both physically and politically.
As you can see, Obama outperformed Kerry in Kansas, as he did in 42 states. The real area of decline for Democrats was the northwestern quarter of the state, including the town of Hays. This area is somewhat ancestrally Democratic, at least as far as Kansas goes; Bill Clinton won the county containing Hays, although in some counties in the area he came in third behind Ross Perot. However, it's important to keep in mind how sparsely populated rural Kansas is. Leavenworth County, in exurban Kansas City, is another problematic county for Democrats, probably due to population growth. There are some other sparsely populated counties that got redder as well.
For Democrats, as everywhere, the cities and suburbs have solidified. Sedgwick County (Wichita) and Johnson County (KC Suburbs) are the big growth engines, responsible for 23,000 of the 53,000 net vote gain in the state. All the rural counties combined were responsible for only 16,000, with a fair amount of that centered in the towns of Liberal, Garden City, Dodge City (all in the west and diversifying) as well as Manhattan and Emporia. Shawnee County (Topeka), Douglas County (Lawrence), and Wyandotte County (Kansas City) have all seen some growth as well. Kansas is actually very representative of the country in this way. Cities are good for Democrats, suburbs are good to fair, and exurbs are bad in terms of improvement, while rural areas can be all over the place.
In neighboring Nebraska, it's a similar but bluer story. 
Only 5 counties got redder, and 2 of them are massive in geography but not so much in population. One county stayed exactly the same, while the rest got bluer. Democratic growth was mainly in Omaha-Bellevue, as well as Lincoln. Moderate gains were seen in Kearney, Hastings, Grand Island, Norfolk, and pretty much anywhere with over 10,000 people.
Minnesota has lots of red for a blue state due to its ancestral Democratic heritage in many rural parts of the state. Only 18% of the growth came in the rural areas, which make up 31% of the state's vote.
The Democratic gains, as always, are concentrated in the cities and inner suburbs. 61% of the increase comes from Hennepin and Ramsey Counties alone. If Dakota, Anoka, and Washington (the suburbs) are included, that increases to 79%. Southern and Northwestern Minnesota both showed Democratic improvement, particularly in Mankato, Rochester, Moorhead, Crookston, and Bemidji. For Republicans, good news can be seen in the outer suburbs; Democrats barely gained in Scott and Carver counties and lost ground in Wright and Sherburne. Furthermore, like union Democrat areas nationally, the Iron Range is getting worse for Democrats, although it's still quite blue. Finally, Central Minnesota, including St Cloud and Morrison County, look better for Team Red.
Indiana was surprise win for Obama in 2008, but it stayed far better than 2004 numbers last cycle. 
Personally, I'm surprised how well Obama held up in Southern Indiana compared to other Border South areas. Southwestern Indiana, where this is coal, is his lone weak spot, along with two random counties in the north and some of exurban Cincinnati. Nearly every population center improved substantially. Marion County had huge gains (31% of the state's gains), and the corridor from Gary to Elkhart improved as well. Fort Wayne, Kokomo, Evansville, Bloomington, Muncie, Anderson, and Lafayette all did well. Obama underperformed in Terre Haute but still overperformed Kerry. One area missing: the suburbs of Indianapolis. They barely register here, making up 13% of the state's population but only 5% of Obama's improvement. Democrats' goal should be to make more inroads here, as they saw better numbers in most other midwestern suburban areas. As you can see, many rural counties also saw good numbers for Democrats; they are the second lightest shade of blue rather than the lightest as is the case in Minnesota.
Finally, we get to Missouri, where the bottom fell out for Obama in 2012.
There are merely 11 counties in the state where Obama outperformed Kerry, and in fact this is one of the 8 states where he underperformed him in total. 3 of the 11 have large Black populations: St Louis City, St Louis County, and Jackson County (Kansas City). Five more have population centers: the towns of Springfield, Joplin, Columbia, Jefferson City, and Sedalia all had good numbers. However, minus the other 3 random counties, there were bad numbers everywhere. The St Louis suburbs and exurbs are brutally red, as are the Kansas City exurbs, a big contrast from the numbers across the border in Kansas. This is apparently what happens when you go from competing in a state (2004) to not competing in it (2012).
And that concludes Part 3.