The first thing to highlight about Pretendo NDS Emulator is that it lets you load ROMs in .rom and in .ds format, as well as in compressed formats (.rar and .zip). That said, it's important to know that you have to acquire these ROMs legally, and that the emulator doesn't offer any by default.
The control system in Pretendo NDS Emulator is very well done; it features virtual controls that are identical to that of the Nintendo DS, and at the same time it lets you use your finger as a stylus on the lower side of the screen. The result is an almost perfect control over your games.
Among the most interesting features in Pretendo NDS Emulator you'll find an autosaving option, that will automatically save your progress every so often; you can also deactivate sounds and graphics, gaining in emulation performance.
Pretendo NDS Emulator is a good Nintendo DS emulator for Android. Its main defect is the amount of ads it shows, too many for its own good, which also causes some instability.