nds4droid is described as 'free, open source Nintendo DS emulator written for Android smartphones. It is based off of the excellent emulator DeSmuME' and is an app in the Gaming Software category. There are more than 10 alternatives to nds4droid for a variety of platforms, including Windows, Linux, Mac, Android and Xbox. The best alternative is RetroArch, which is both free and Open Source. Other great apps like nds4droid are higan (Free, Open Source), Nostlan (Free, Open Source), No$GBA (Freemium) and RetriX (Free, Open Source).