Ever since it was announced as part of Bethesda's E3 2015 press conference, Fallout Shelter has been the game to watch.
Immediately available and heavily pushed on the Apple App Store, it was soon dashing up the download charts.
And despite a maximum IAP of $20, it also quickly climbed the top grossing charts, generating headlines when it took the #3 position from Candy Crush Saga in the US, albeit not for many days.
For, as our Monetisation Mavens pointed out, the game isn't structured for longterm success.
It doesn't have any inbuilt virality, let alone a multiplayer mode, and it's uncertain if the content will be updated regularly enough to stop power players running out of things to do.
Nevertheless, two weeks on, Fallout Shelter is still a top grossing game; something this week's Charticle makes clear.
All guns blazing
In the main English-speaking countries - Australia, Canada, the UK and US - Fallout Shelter has found its most receptive audience.
This isn't a surprise, as these are countries where the post-apocalyptic franchise has historically sold best on PC and console.
As the chart shows, Fallout Shelter launched very strongly - into the top 10 on iPhone in all 4 countries.
Into its second week, you can see its decline, which is accelerating although it's only just outside the top 10 in the UK and Canada. Only in Australia is it outside the top 20; an impressive performance indeed.
Looking at the iPad grossing chart for the UK and US, we see a similar trend, with Fallout Shelter performing best in the UK.
In general, the game is positioned higher in the iPhone than iPad grossing charts, as you'd expect given its quick drop-in, drop-out gameplay.
Checking out the game's position in key European countries for iPhone, strong Fallout market Germany is the best performing.
France and Russia have been weaker but in all three cases the game remains within the top 30; another strong position for Bethesda.
As is often the case with western brands, the key Asian markets - China, Japan and South Korea - typically provide a barren reception.
To some degree this is also the case for Fallout Shelter as we've had to rebase our graph from a top 50 to a top 500.
Yet, the game has gone top 100 in South Korea and China, even if it's since fallen out. Only in Japan - the most singular and locally-focused mobile game market in the world - has Fallout Shelter failed to make any impression.
Continuing with Asia, we've also taken a quick look at Hong Kong and Taiwan: two markets sometimes similar to China.
As can be seen, the more western tastes of Hong Kong see Fallout Shelter doing significantly better than in China; it remains in the iPhone top 100 grossing chart.
The Taiwanese clearly aren't fans of the brand; indeed as with South Korea, it's more of an Android market anyhow, so perhaps we'll revisit the situation if/when Bethesda releases Fallout Shelter on Google Play
In conclusion, then, as predicted Fallout Shelter quickly peaked in terms of its global top grossing position and is now in decline.
But despite its weaknesses in areas such as IAP economy, community and even gameplay longevity, the surprising thing is that the combination of addictive gameplay, strong brand and fanbase, and perhaps even its gacha-lite monetisation (you can't directly buy hard currency), are keeping the game higher in the grossing charts of some of the most competitive markets than we would have expected a week ago.