Hetalia's main presentation is as an often over-the-top series (with can be interpreted to reveal a hidden meaning; a moral) of political and historic events as well as more general cultural comparisons. Characters are personifications of countries, and regions and micronations such as the Principality of Sealand, with little reference to other national personifications.
Both positive and negative cultural stereotypes form part of each character's personality-often people can find this offensive, but it's not meant to be serious-mostly-it's a comedic relief.
Each episode is only five minutes and can go from one historical moment to the other, but in the end it all adds up.
At first you mostly focus on the main countries, but as the story continues, in each series you gain more knowledge about history, as always:laughter, and many more countries, nations/regions, micronations, and historical well-known people on the side.
As you really get into this series you'll find that history can be hard on these nations-and you form attachments to each one. So, as being a parody of history, Hetalia can also be serious, and very emotional, since you've now seen personified countries, and how history can be so very hard on them. It has you realize that the world would be a better place if all countries got along together.
Series One: Hetalia; Axis Powers
The the main characters are the countries which made up the Axis Powers (Italy (North Italy in particular),Germany, Japan) and the Allies of World War II (United States, England, Russia, China, France and Canada).
They focus on these characters and the time period they're in-around World War II-usually at 'World Meetings' and getting ready; both the Axis and the Allies. They add in some old historical moments, too, which features other countries, nations/regions, micronations, and historical well-known people on the side for more history and comic-relief.
In this series (and all the others) we have Chibitalia (chibis of nations showing us past experiences they've had-a time period (like childhood) when they'd recently become a nation; or not nearly as old and grown up as they are now).
Series Two: Hetalia; World SeriesEdit
In this series we still have our main characters, but many more countries, nations/regions, micronations, and historical well-known people on the side are added in. It's now all about the world, and each part of history. They now have many more characters, and show them ineracting in historical events.
We still have Chibitalia, for a while (look in season one's description), and then they added in Nekotalia which is where the countries are now cats. (Chibitalia and Nekotalia are side breaks from the big picture, but also include history and comedy)
Movie: Hetalia; Paint It WhiteEdit
In this movie, the main countries from Series One: Axis Powers, all have to join with each other as a team to protect the World from aliens (Pictonians)! They go in disguise and attack, but then have to pull back because the Pictonians are pushing in on them. The Allies and the Axis Powers fight as one to keep the World safe.
Series Three: Hetalia; Beautiful WorldEdit
In this series, first of all the art has changed to the original manga art style! (Hetalia-the manga-was created by Hidekaz Himaruya). It includes more and more comic/manga strips Hima-papa has created. Which include more of the emotional times in history, how the countries live forever, which is a curse and a gift. They now have included more countries and nations, etc. that are in the comics, as well! Beautiful World includes Gakuen Hetalia (Hetalia Acadamy), and many more laughs to be had, history to be learned (in a fun way), emotional attachments to the countries, and all of the rest of the world Hetalia has included so far, become stronger than ever.
They also include mochis this time around~ (nations as mochis).
Switzerland and Liechtenstein
Ukraine and Belarus
The Three Baltics
(Latvia, Estonia & Lithuania)
The Five Nordic Countries
(Switzerland, Finland, Iceland, Denmark & Norway)
Holy Roman Empire
(Hong Kong, North Korea, South Korea & )