After the last big update which offered a big improvement it is funny that he had to backtrack a bit as he had changed the sound of the filter a bit, purists got upset and he changed it back. In this update he have remodelled the filter again to make it closer to the original Gameboy version. So I guess now you can fool any purist with your Android device!
Another thing to take into consideration is that you can actually buy a secondhand Gameboy for almost nothing. A short research on available Gameboys in the City I live in
( Valencia, Spain ) there is about ten / fifteen Gameboys to be had from ten euros to about 25 euros. Plus that you can get the Nanoloop cartridge that the developer is still producing for around 30 € and up.
So for not too much money you can go Chiptune visually to,
waving a Gameboy in the air...
Homepage with cartridges for sale: