iNDS is the world famous port of the multi-platform Nintendo DS emulator to iOS.
Currently, emulation is powered by the DeSmuME threaded ARM interpreter and runs at nearly full speed on the iPhone 5 and above. You can get even up to 60fps on newer devices.
Customizable interface, where you can select a preferred controller size and mic
Auto-saving game progress
10 image filters for the ultimate picture quality
7zip and RAR files are available straight from the app
Over 100 000 cheats are included
In-built bug reporter
Slow performance on some gadgets
Due to the need to mmap the entire ROM into memory, older devices with only 256MB of RAM are not supported. These devices include the iPod touch 4, iPad 1, iPhone 3GS, and anything below those devices.