I recreated the original Flappy Bird game for the Nintendo DS with libnds and NightFox's Lib. You can download and modify the project to learn how to create a 2D Nintendo DS game. Feel free to create a pull requests to improve the game :)
On emulator
On a real Nintendo DS
How to run the game
Download Flappy_Bird_DS.nds here.
Run it on emulator like melonDS.
For a real Nintendo DS, you will need a R4 flashcart, may no work on other flashcart like M3DS REAL (flashcart needs nitrofs support).
For R4, you will need this firmware (Wood R4 V1.62).
For other flashcarts, try HBMenu if you can't launch the game).
Put the game on a SD card and run the game.
Download an IDE software like Visual Studio Code.
Download devkitPro.
Put all projects files in a folder and put this folder in "examples" devkitPro folder like: C:\devkitPro\examples\Flappy_Bird_DS.
Open the IDE console and write make or run compile.bat
The Nintendo DS game file will be here : C:\devkitPro\examples\nds\Flappy_Bird_DS\Flappy_Bird_DS.nds
Have a good game ^^