The Torchlight achievements are generally buggy. I had quite a few problems with them myself, most of the time exactly like you describe it - a counter stopped working. (In my case it was for sold items and killed trolls, if I recall correctly.)
So you're not alone (look e.g. here), and there probably isn't much you can do. :(
Edit: It just occured to me: saving achievements doesn't seem to work when you're offline. But somehow I presumed that would not be your case.
Disclaimer: This is very much based off of this Steam forums post. I didn't write it, but I've tried to expand it a little, based on my own playthrough to get the achievement.
First of all, you do need to beat The Rise of Africa before you can do this. It shouldn't take you all that long, and you'll get a (very!) basic feel for how the game works.
After that, play the Fuel Crisis scenario. Start by recruiting a single agent in all regions except Africa. Create a Regional Technology Office in each location, and end the turn.
On the second turn, replace agents that have gone missing, add an agent in both Africa regions, and give them a tech office too. Set Japan to research Energy, and create a Political Office everywhere else. End the turn.
Keep Japan on Energy research until they discover CCS. Everywhere else, try to keep your hearts up so they don't ban you too early, and when you don't have anything else to do in a region, have them commit to nuclear energy. You will also want to play the Black Ops card in the more stable parts of the world; this will help you later.
When Japan gets CCS, have everyone else acquire it. Keep Japan on research.
The next turn, you should get 4th generation nuclear energy in a couple of regions. For those regions who have not gotten there on their own, acquire it.
From here on, simply commit to nuclear everywhere. In the more stable regions, play Fund Insurgency Campaign to reduce stability, then commit to nuclear. Keep doing this, and hopefully, you will quickly reach a global thermonuclear war.
If you fail, try again - there's a fair bit of RNG involved in this game, so you might get banned too quickly, or miss the target before you cause enough instability.
TL;DR: Get tech offices for everyone, have Japan research energy, import CCS and 4th gen nuclear everywhere, commit to nuclear and reduce stability.
Best Answer
There is some confusion around this achievement. Given the potential time investment, many people are unwilling to experiment too much. There were also some bugs with it on the PTR, so some of the existing information is slightly out of date.
It appears that the character must have been newly created after the event starts. Some players report that if they use preexisting level 1 characters, they do not receive credit.
This is not a problem - the character must be level 1 when entering the game. I had some overpowered cube effects on my character and AOE-killed some mobs in Old Tristram on the way to the portal and hit level 2. I still received credit.
Yes. If you are disconnected, either offline from Battle.net or completely kicked out of the game, you will not receive credit unless this occurs before you hit level 2. When your character reenters the game it will not be level 1, and will not meet that requirement.
Absolutely. Many players use the Gem of Ease and Kanai's Cube to give level 1 characters level 70 gear, even full sets. Hellfire jewelry is relatively easy to craft and gives a huge boost since it has level 70 stats but no level requirement. Paragon points are fine, too: it is an easy way to give a good boost in a primary stat.
Note: if you craft any gear (e.g. Hellfire jewelry), be sure to craft it on the level 1 character or another character of the same class. Otherwise, you run the risk of junk stats. For example, crafting the Hellfire Amulet of Strength may give wizard ability bonuses if crafted on a wizard, despite being targeted at a barbarian or crusader.
Yes, feel free to portal back to town to empty your inventory.
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