Fallout Shelter, the spinoff mobile game from Bethesda's critically acclaimed Fallout series, will launch on Android this Thursday, 13 August, after achieving massive global success on Apple iOS.

Following its release on the App Store for iPhone, iPad and iPod touch in June 2015, Fallout Shelter quickly became the most downloaded game in 48 countries and the top downloaded app of any kind in 25 countries.

The game, which offers in-app purchases, also rapidly climbed the ranks of the highest grossing apps, raking in $5.1m (£3.3m) in its first two weeks, according to sales tracking organisation SuperData.

Fallout Shelter is set in a post-nuclear wasteland, where the player is in control of a state-of-the-art underground vault. Using a selection of tools, they must build the perfect vault, oversee a community of vault dwellers and protect them from the dangers of the wasteland.

The game has been praised for its fun, addictive gameplay and visual features, but criticised by some for its clunky controls and long load times on some devices. It is currently rated 65th in App Annie’s list of top grossing iOS apps.

With the Android launch, Bethesda is clearly hoping to tap into Android’s 78pc share of the smartphone market. When it launches on Thursday, the Android version is billed to include new enemies such as “mole rats” which attempt to infest vaults and “deathclaws” which launch invasions on shelters.

There is also a new robot called Mr Handy, which can explore the wasteland, collect resources for the vault and fend off enemies.

"We are going to support Fallout Shelter for a long time," Todd Howard, Game Director at Bethesda Game Studios, told the crowd at QuakeCon a few weeks ago. "This is something we did on the side and we were blown away by the response."

Meanwhile, Fallout 4, the fifth major installment in the Fallout series, is due to be released on Microsoft Windows, PlayStation 4, and Xbox One on 10 November. Various outlets have already begun accepting pre-orders and fans buying the game now can find a range of deals.

The game’s official trailer, created at Bethesda Game Studios, can be viewed here:

The first two Fallout games, released in 1997 and 1998 respectively, were created by Interplay Entertainment and developed by Black Isle Studios. Bethesda purchased the franchise in 2007.

Fallout 3 was released in 2008, followed by Fallout: New Vegas in 2010. Although Fallout: New Vegas offered a similar action role-playing experience to Fallout 3, it was not a direct sequel, whereas Fallout 4 is.

Fallout 4, announced at the Electronic Entertainment Expo (E3) in June, will be set in Boston exactly 200 years after a war over resources that ended in a nuclear holocaust in 2077. The player's character is free to roam the wasteland with his canine sidekick, picking up weapons and defending his base from other survivors.

Some observers have criticised the relatively underwhelming graphics in the trailer. However, those who saw the latest extended trailer of gameplay atGamescom this week praised its detail and vibrancy.

For many Fallout fans, the downfall of both Fallout 3 and Fallout: New Vegas was that once the game was over, they weren't able to head back into the wastelands and continue their exploration. However Bethesda has confirmed that this won't be the case with the upcoming Fallout 4.

To our fans who’ve asked: Fallout 4 doesn’t end when the main story is over and there is no level cap. You can keep playing and leveling. — BethesdaGameStudios (@BethesdaStudios) August 6, 2015

Fan frenzy over the launch of Fallout 4 is now reaching fever pitch. In June, a gamer named Seth placed a preorder for Fallout 4 directly from Bethesda Softworks, paying for it entirely with bottle caps (the standard currency in the Fallout series) – 2,240 in total.

He admitted that he wasn't sure about the caps-to-dollars exchange rate, but said he hoped his post on Imgur would become popular enough that "their PR department will be too nervous to turn me down." His audacity paid off, and Bethesda promises to send Seth a copy of the game in November.

Meanwhile, the “Pip-Boy” edition of Fallout 4 has already sold out. The collector’s edition costs £99.99 and includes a wearable Pip-Boy replica, which comes with a Robco Industries stand, custom-printed capsule and working knobs and lights.

Gamers can slip their smartphone inside the Pip-Boy wrist mount and, when used in conjunction with the Pip-Boy mobile app, manage their in-game inventory, perks and holotapes as if they were an actual vault dweller.

Bethesda has confirmed to Gamespot that it won't be making any more Pip-Boy editions, because the factories do not have enough capacity.

“We reached a point where we'd go back to the factories and they were like, 'guys, this is it, sorry’,” said Bethesda's marketing VP Pete Hines.Another Bethesda product in the franchise – Fallout: Project Brazil, a major story modification for Fallout: New Vegas that will be free for owners of the latter – is in a race to release ahead of the main series sequel.

Project Brazil leader Brandan Lee has said that he wants to push out the mod before fans move on to Fallout 4. However, the project would have to be completed several months ahead of schedule if it were to beat the Fallout 4 release date.