Such was his stress, Nguyen said he couldn't sleep, but now the game is gone his conscience is clear.
"I don't think it's a mistake," said the 29-year-old. "I have thought it through."
He will continue to develop games, and has several other top App Store games, including Super Ball Juggling and Shuriken Block.
He has no plans to remove those two, calling them "harmless".
However, if he thought players were getting addicted, he would not hesitate to also take them down.
Last week Nguyen's estimated daily take from Flappy Bird in-app advertising was US$50,000.
"I don't know the exact figure, but I do know it's a lot," he said.
- Gameplanet