How is the German nationalism? I understand that currently, Germany is a country with lots of different Germanic people and other countries like Austria, France (Alsasia?), Switzerland, Liechtenstein and others have also Germanic people living in. Do the people in Germany feel like they are GERMAN?

Germans see themselves as Germans, but also quite frequently will focus on how they belong to a specific group inside Germany. This can be humorous like the distinction between Cologne and Duesseldorf, or bordering on separatism (Bavaria has a small but vocal separatist group that want Bavaria to split off from Germany. Quite a few Germans outside Bavaria think that's an excellent idea....). You have to realize that while Germany has been a single country since the late 19th century, it WASN'T for centuries - so there's still loads of cultural and language differences to bridge. In fact, regional heritage is so important, one of our government parties (the CSU - from Bavaria, of course...) assigns ministerial posts in the federal government not by competence for the field, but by which region of Bavaria the candidate is from (I wish I was joking there - but today they assigned their expert for defense to be new minister of Agriculture - because they needed a candidate from Franconia).

"Do the people in German feel like they are German"? what do you mean? sure there are a lot different German groups in the curent German population of originally different teutonic/germanic tribes but that is long in the past. After the WWII west Germans are like brainwashed anew that nationalism is evil. But the east Germans dont have such a problem with it cuz ex-East Germany was considered as one of the winner states. But still, if you come up with such a discussion in Germany about common language and cultural backgrounds of all German speaking population in Europe you need to be careful, cuz you can be easily get blaimed for propagating nationalism because that was exactly the main excuse for Hitler to start conqureing other European countries in the beginning. Btw, you forgot to mention a small area in north Italy called South Triol. Nowadays German dont think about it this way any more. Germany is Germany, it doesnt make other groups of population German only because they speak German or were once part of Germany. And that has nothing to do with nationalism, actually. If you ask an Austrian, most answers you might get is that they never saw themselves ever have been part of Germany.

German nationalism to many in Germany means to accept the conditions of the winners - the Prussians who dominated and seized most of Germany in the mid-19th century and later set the cultural norm with their "Kaiser".

No, "Swiss-Germans" feel less and less Germans and since the rise of nazism, try the distance themself from Germany (der grosse Kanton), especially using their dialects everywhere. Note, in Switzerland, using the word Swiss-German (or Swiss-French), is considered slightly insulting, using Swiss-Alemanic instead (or Romand/Welsch for the "French").