Hearts of Iron IV

Your goal is to build EU union. Overall it will take about 40 minutes to get this achievement with max speed ingame. Might have to restart your game if civil war does not go the way it should

Follow this tree:

1. Repeal the may constitution
2. Regulate the finance sector (Chose 2nd option) - Triggered german civil war for me and Facist germany has to lose.
3. Economic Resucitation
4. Devalue the schilling
5. Legalize political opposition
6. Hold Elections (Pick Karl Renner)
7. The Danubian Federation
8. Invite The Danubian Countries (but dont invite anyone)
9. Danubian Unity
10. Inviting the observers
11. Danubian Diplomacy
12. Via The danub to Europe (Invite Kingdom of Germany to EU union)

Now you need 500 to Annex germany. Once that is done achievement is yours 😃

There are alot of YT guides aswell about it in different ways if this does not work. But this seemed to be the fastest way i could do it myself.

From the newest DLC this is probably the easiest achievement to get.
You either have to own the DLC yourself of do the subscription to hearts of iron 4 to get all game content.

Dam busting raid can be done against Belgium so play German Reich and play it out normally as you do but before conquering Belgium do the Raids on them.
Raids usually need strategic bomber and tactical bombers.

Fastest way to do this is with United Kingdom and Revisit Colonial policy branch.

UK has 14 colonies as puppets at the start of the game so you just need another 6

Key points here is to join Axis side before ww2 starts, otherwise germany will conquer you.
To join axis you must focus on becoming facist side.

This is best done as Germany, Since they start with the shortest doctrines already.
Advisable to disable all DLC's for it.

Note: Naval dockyards count as factories aswell.
Can be reached by going Fascist (so germany wont attack you) and conquer the netherlands quickly.
Joining Germany will also mean you get northern france easily which adds towards the goal of factories.

Follow the Axis path and join the Germans. That way germany do not attack you, this also means Axis is guarding you from the Soviets so you can freely research your rocket technologies.

Fastest way to get this done is to go Facist. Rush Submarines II and start to justify against Denmark. You need about ~10-15 submarines and when justification end, declare war. Capture a port in Greenland and then Invade Iceland. As soon as you land on iceland (Port tile) the achievement pops

Do the Following:

Become communist and put Trotsky in charge

Research:

1. Plan of Agua Prieta
2. Legacy of Revolution
3. The Red Shirts
4. Internal Struggle
5. Filler what you like
6. Revolutionary Class War
7. Spanish Civil Refugees
8. Support Spain Loyalist
9. Bolivarian Alliance
10. Filler what you like till Germany Declares war on Soviet
11. When Germany Declares war on soviet rush "Smash the Bereucrats"

Ask military access from germany and go attack soviets.
You have Puppet Focus so also declare war with that. Most likely you will win the war and then can puppet soviet and achievement unlocks

These achievements can be earned at the same time.
Promote a divisional commander to general as soon as you can and give command of an army. Grind the XP during Sino-Japanese war as much as possible. Switch the general between different divisions so you can gain more XP when pushing back Naval invasion (Japan constantly naval invades you). After you have control of China and united it again then you can war India for the rest of the Xp.

This basically means that you have to Drop a Nuclear bomb on Tierra Del Fuego.
Fastest way i found this to do is when you play as France you can declare war on Argentina. use your colonies on south america to simply drop a nuke on them, you can declare war on all the fascist countries in south america so conquering some you need isn't a problem.
Easiest would be if you get faction leader of the allies.

Other way to do it is to play Argentina yourself, and release Wladychfa Gymreig as a free country and then do a wargoal and drop a nuke.

This works as combined 2.

Rush "Exploit The Weak Neighbours" focus and that will grant you to conquer Shanxi and Xibei San with your starting army.
When the focus ends justify on Sinkiang so when you are done with conquest you can declare war with them.

Make a deal with China to fight against Japan at start and then focus doing infiltrations and build up your army at the same time.
When you are ready execute infiltrations (take them further) and war with China will begin.

You will be fighting 2 fronts. If it comes to a stalemate then just wait untill Japan Declares war on USA and then US will join you in the fight. Now it should be easy to take both China and Japan down.
You have enough victory points to claim all China core territory giving you "The People Have Stood Up!" after that just build military factories and stay fairly neutral and you have "Made in China" done aswell

For The Lion that Roared:

This requires you either to push Italy into the seas or to keep holding until the AI has had enough and offers you peace. Finally, you can also end the war by doing the focus 'Fait Accompli'. This achievement can be done in conjunction with "The Lion King", because 'Fait Accompli' is in the same branch of the focus tree as 'The Kings of Kings' focus.

For The Lion King:

You only need to occupy the required states for the achievement to trigger.
Playing with historical-ai off has a chance of the UK going anti-colonial. In which case you may not have to fight the Allies. Access to the focus "Towards African Unity" is, as before, possible through "Rebuilding the country" focus. Just don't do "Jah" or "The One Tru Heir of Solomon". Still can be done during "This time for Africa" achievement run. Go down "Emperor Stays" path. Defend against Italy. Complete "Support Anti-Colonialist Resistance" Meanwhile, stockpile a lot of infantry equipment (5k) and Political Power (215) you will also need about 125 Command Power. After that go to decisions tab and start using "Support anti-British resistance" options, which are available on the map - first do that in Tanganyika then in other required provinces. Now go for "Anti-British propaganda" decision. Just after resistance strength hits 70 in a given province use "Arm anti-British resistance" in decision tab. Wait till Tanzania break free (it will form from Tanganyika), then same should happen with Kenya (will be formed from other 4 required provinces). Both countries start a war for independence with UK. Use decisions to demand ending the war. If UK accept your demands the country will join your faction - kick it and start justifying, start war, win, annex. If UK will not accept your demands, don't use option to go to war with UK. Wait, there is a chance that UK and liberated coutry will sign white peace. If they do so - start justyfing, start war, win, annex. If they don't do so - start the game all over again.
Another simpler strategy, defeat Italy, wait for Allies to fight Italy in North Africa, get your war goal from focus "Pan-Africanism", declare war on UK and rush the provinces it requires to get the achievement, all you need is to control them rather than owning them.

The key to getting this achievement is Vichy(/Free) France. Both will have low compliance and resistance strength in their African provinces. Making them an easy target for uprisings. Start the game with historical ai on. Push back Italy, but don't accept the peace event neither do the focus "International Mediation". The reason is that you want to max out the guns decision that you get from the focus "Arms Purchases". When you've reclaimed all your cores continue the political side of the focus tree and take the "Empower the Ras" side. The reason you go down the "Empower of Ras" side is that it leads towards "A Federal Empire". This will splinter your nation into many autonomous puppets (which don't count towards the achievement) and a small Ethiopia. But makes it a lot harder for the enemy in case you have to do revolts in Free France (sometimes the part of the French Colonies below the Sahara Desert change from Vichy to Free France). The Allies can then only attack you on a couple of mountainous tiles (unless you decide for some strange reason to call in those puppets to fight with you), which are easy to defend with the 30ish (irregular) divisions you should have at that point. You could build some forts for comfort.
Make sure that around the time Germany declares war on Poland you have a good amount of PP(300+) and Guns (10k+). Once Germany has defeated France and Vichy France has appeared, take the 'Anti-French Propaganda' decision to increase resistance in their African Provinces.
Once that decision is done start boosting resistance in specific French provinces. The order in which you let those African Nations revolt is up to you. However, make sure that they are not . Because if for example Dahomey revolts, they take the neighbor province (core state of Togo) and you were boosting resistance in that province as well. Then once Togo revolts they'll join The Allies (since they revolted against your ally). So only start boosting in provinces controlled by your enemies. Remember to click the demand recognition decision (which appears 24 hours after the revolt), otherwise, they won't join your faction. For the achievement, it doesn't matter if they'll capitulate, only that you have at least 13 African Nations from the list in your faction.
Be aware that when Japan goes to war with the Allies that there is a chance that when a nation revolts that they will automatically join the Japanese faction. But it shouldn't be more than 2 or 3 that do so. If you're unlucky and haven't reached 13 members yet after you revolted all of the French African provinces, go for the Belgian ones or the Portuguese (British is pointless, far too high compliance). Finally, and I am sure everyone knows this. Vichy France is guaranteed by Germany. So once you declare war on them through a "Demand recognition decision" they'll join the Axis. But since you are at war with them anyway that doesn't really matter. Tip: It is better to raise resistance in small or even one-state nations like Rwanda, Burundi or Gambia, as this will lead to an uprising much faster because of fewer states that have to meet the resistance threshold.
Alternatively, perhaps faster and more consistent, but also a more difficult method to get this achievement is to simply go to war with the colonial powers and occupy enough territories in Africa to create 13 collaboration governments, which will count for the achievement once you complete the Towards African Unity focus. Beware that to be able to create collab governments as Ethiopia you need to do the focus "A Federal Empire". This is best done in a run where the emperor stays thanks to the massive boost to compliance gain that the "Elect of God" focus grants. This may be easier on non-historical mode, depending on what factions the colonial powers join. Furthermore, there is a chance that the UK completely decolonizes on non-historical.

Fastest way to do this is to go Facist and get Civil war.
Do not win the civil war with brute force but go as far as to get "Conditional surrender".
Once that happens agree to conditional surrender and the achievement will unlock.

This is not bugged anymore, reports on steam thread of people getting it.

I have to correct myself as my original description on how to get it was a bit misleading.
Play as Raj with Historical AI turned on. Then rush down the East India Company route for hostile takeover. Research Computing and Construction technologies.
You can then release as Khalistan, but you do not inherit any Raj technology.

More can be read from HOI4 Wiki where i took the route how to take it - https://hoi4.paradoxwikis.com/That%27s_Sikh!

Other option to get this is:
Starting as Raj → Go Communist path that makes you release Pakistan, capture pakistan again and then take the focus that allows you to create factions. Release a single state and make a faction with them. This prevents India from joining Cominterns or any other faction. After that release yourself as Khalistan and start the rampage.
To conquer India you have to delete all their units and infrantry templates and productions.

Fastest way to do this is to go fascist and join the Axis powers in attacking Soviet Union. Mongolia is in faction with soviets and Germany usually does not want it .
So get some war score to just gain mongolia.

Note: This does not Require Graveyard of Empires DLC.

Take a Decision to improve workers condition and do alot of anti-fascist raids for more stability. Just Build infrastructure in all your states and stay as neutral as possible.
Take Construction effort and infrastructure effort focus to get it faster

Best way to achieve it is to go "non historical AI" then select Custom game rules and set Poland and UK as historical.
Soviet Union and Germany have to go to civil war and lose. If that wont happen restart the game and try again.
You can either go facist yourself or stay non-aligned.