The game, developed by Ha Noi-based Nguyen Ha Dong, dominated the download charts of both Google's Play Store for Android and Apple's App Store for the iPhone before its removal on February 9. It was reportedly downloaded over 50 million times, generating US$50,000 per day in advertising revenue.

Ho Minh Duc, deputy general director of Naiscorp, noted that the high number of users playing the game had been the source of its fame, allowing the developer to obtain information on the players' demands and to update the game to make it more appealing to them.

With his experience of working at Naiscorp, which develops Socbay iMedia – totalling 22 million downloads, making it one of the four most downloaded games in Asia – Duc pointed out that the success of Flappy Bird was also dependent on understanding the market and, in some part, on luck.

"A game should be simple and attractive to most users. The success of Flappy Bird and Candy Crush Saga are typical examples," he said.

Le Van Giap, founder of Vietandroid.com forum and ViMarket.vn app store, claimed it was not difficult to create such a game and even an average developer could do it.

However, Flappy Bird is an unusual game in that it addresses the psychological needs of the gamers.

Regarding its $50,000 in revenue per day, Nguyen Duy Hien, admin of Appstore.vn store, admitted that the amount was remarkable. Hien said Vietnamese games with millions of downloads have gained only a few thousand dollar per month.

"In my opinion, Flappy Bird is a new phenomenon in the Vietnamese game industry, with a different method of playing, spurring players on to get higher scores. There have been similar Vietnamese games before, but none were as good as Flappy Bird," he stated.

Giap acknowledged that news of the revenue earned by the game had come as a shock because no Vietnamese games had ever earned so much money from advertisements.

Meanwhile, Duc suggested that amongst global games, Flappy Bird's revenue was still lower than that of other popular games, and there had been scope to increase revenues in the future.

Last Sunday, Dong took down the game from online stores after making the announcement on his Twitter account.

In an exclusive interview with Forbes on Tuesday, he said the game was "gone forever" because "it happened to become an addictive product."

The American business magazine reported that the interview had been delayed by several hours because Dong "had a sudden meeting with Viet Nam's Deputy Prime Minister Vu Duc Dam."

During the meeting, Dam had encouraged Dong to pursue his passion and stated that talented Vietnamese such as Dong are contributors to the nation's development.

On Monday, Stephen Totilo, Editor-in-Chief of Kotaku.com, a news and opinion site reporting on games, sent an apology to Dong for their comments on the game's art.

Jason Schreier, writer of the original "Flappy Bird Is Making $50,000 A Day Off Ripped Art," also apologised to the developer for his "poorly chosen words."

The article was given a new title: "Flappy Bird Is Making $50,000 A Day With Mario-Like Art."