Flappy Bird was comparable of other games Nguyen had previously released on mobile devices, such as Shuriken Block or Super Ball Juggling. The graphics paid tribute to retro sprite art, the gameplay was very straightforward, and the difficulty was set to a high level, which caused short game sessions.

The concept seemed incredibly straightforward: Tap the screen to ascend, let go to descend, and access through openings in a sequence of green pipes that were clearly prompted by the ones in the Super Mario series. The gaps were generously spacious, considerably more than the bird's height. However, navigating through the narrow gap without losing control was quite a difficult task, given the bird's rapid movements and sudden dives. Considering that you only receive one point for each pipe cleared, it is highly probable that your high score will be in the single digits, if not zero.
For months, Flappy Bird had a similar level of success as Nguyen's other games, meaning that it didn't gain much popularity. In late October, a small update was released to address some bugs. After a few days, there was a noticeable shift - another person, not Nguyen, was the one who put out the initial tweet regarding the game.

The game was frustrating, yet captivating. And since people often seek solace in shared experiences, players who discovered it wanted to express their frustrations. In November, Flappy Bird gradually gained more users. Reviews started coming in gradually: one per day, then three, and eventually 20. The growth of Flappy Bird appeared to be solely driven by players sharing their mixed feelings about the game through word of mouth. Nguyen graciously engaged with his steadily increasing fan base on Twitter, even making a commitment to bring the game to Android.

Flappy Bird managed for getting to 80th spot on the U.S. App Store's "Free Games" chart by the end of December. After that, it departed. The game's popularity soared as a growing variety of users turned to Twitter to express their frustration with its hard nature. Nguyen was thrilled as Flappy Bird climbed the ranks to become one of the top 40 most downloaded free iPhone games. It ultimately reached the top 10.