Hi Dear!
Can it be downloaded to an Android mobile device?)
For Android, my current recommendation is Lemuroid. I think it's a frontend for Retroarch that's designed to be easier to use, and it delivers on that front.
(It's also on F-Droid if you don't want to use Google Play.)
iPhone/iPad users can also play, by using an emulation suite like Delta, or a dedicated Game Boy emulator like Sameboy.