I launched the app. It asked for permissions. This is another critical checkpoint. A Dreamcast emulator needs access to your storage (to read the game files, or ROMs). It doesn't need access to your contacts or camera. I checked the permissions; it only asked for storage. A good sign.
: Official development on the original nullDC codebase stopped around 2010. 3. The Rebirth as Reicast
When users search for the they often expect an official port. The truth is: There is no official NullDC for Android.
Here are the two best alternatives that outperform any non-existent NullDC APK: