It’s not a perfect 1:1 port, but for a DS homebrew title from 2011, it’s remarkably polished. The ROM file ( .nds ) is around 4 MB and runs on most emulators and flashcarts.
Navigating menus with the D-pad and firing with the stylus offered a level of consistency prized by high-score hunters. Emulation and Compatibility Angry Birds Ds Rom
Why skip the DS? By 2010-2012, the DS was at the end of its lifecycle. The 3DS had just launched, and Rovio prioritized devices with touchscreens as primary input—something the DS had, but with lower resolution (256×192 pixels) and less processing power than a modern smartphone. The DS lacked the memory to run the full Flash-based or native mobile versions smoothly. It’s not a perfect 1:1 port, but for