Bethesda Softworks blindsided its core following of hardcore gamers with Fallout Shelter, a free-to-play mobile game that is exactly as advertised. The absence of paywall and a solid 10 hours of gameplay earned Fallout Shelter $5.1 million in revenue in it's first two weeks, and it still isn't out on Android yet -- it's coming.

When Bethesda announced it would host its first ever E3 conference, the gaming community expected the video game developer to announce the next entry into its critically acclaimed Fallout series. And it did. But Bethesda also announced that Fallout fans would have to wait until the fall arrival of Fallout 4 to chew on more content from the nuclear wasteland.

Emerging from the Vaults

Giving gamers no gap between reveal and release to nitpick and naysay, Bethesda announced, during its E3 conference, that Fallout Shelter would be immediately available for download on iOS. Since then, Fallout Shelter has smashed King's Candy Crush on the charts to become the top grossing mobile game last month, according to a report from SuperData Research.

Fallout Shelter's $5.1 million in revenues in its first 14 days out and its meteoric rise to the top of the charts underscored the importance of a standout franchise in a crowed market for mobile games, according to SuperData Research.

"More significant than the publisher's success is the notion that core gaming fans proved to be willing customers for a free-to-play mobile game," states SuperData. "By emphasizing unobtrusive monetization and offline playability, Bethesda managed to earn the respect of a consumer group that is otherwise highly critical of free-to-play monetization."

The Other Half of the Story

While the iOS crowd has been managing the lives of vault dwellers seeking shelter in the aftermath of a nuclear apocalypse, Android users have had to monitor the action from afar via "Let's Play" sessions and the like.

Bethesda has been kindly pointing Android users to August, the window for Fallout Shelter's arrival on Google's Play store. Earlier this month, Bethesda Mouth piece Pete Hines, aka "Shake Zula, the Mic Rula" stated on Twitter that the Android port of Fallout Shelter was moving along just fine.

@kolos_kovacs coming along nice. haven't announced a date, but should be out next month. we'll let you know when we have specifics

— Pete Hines (@DCDeacon) July 1, 2015

Forbes' Paul Tassi predicts that Fallout Shelter is about to hit a wall. The problem with Bethesda's monetizatoin of the game is that there's no end-game, he writes. After awhile, there's little incentive to buy more equipment for the vault dwellers.

"After you build all these floors and outfit all these citizens in the best armor and weapons, there's nothing for them to do other than putting out the same fires they did on day one, or fight invading bandits on a loop," Tassi writes.

Again, all valid points. But Bethesda is taking the money, because there's an opportunity to do so. As our friends over at SuperData Research describe it, Fallout Shelter is a marketing tool to build hype for Fallout 4. Fallout Shelter's revenue will inevitably fall, but the Android release should come just in time to give it another a surge.

And when that's all done, we finally get a proper, AAA follow-up to 2010's Fallout: New Vegas. Fallout 4 is set to arrive on PS4, Xbox One and PC on Nov. 10. The Android release should drive the hype train straight to launch. The absence of an endgame in Fallout Shelter proves that Bethesda is still firmly focused on core games and gamers.