Bgm loop? I guess that didn't load for me! all I got was silence and SFX... the SFX ofcs are very nice, crushed and squeaky, which perhaps was what suggested something chipish to my mind...
Yeah man nanoloop is really fun - once you get the hang of the interface it's a really intuitive, easy to use step-sequencer. I made that album with the nanoloop 1.3 cartridge on a DMG (grey brick gameboy), also have nanoloop 2.0 for the GBA. Fun to do it that way, though probably a lot easier on the eyes doing it via an app! And the sound quality is probably comparable, as I assume the app emulates the DMG hardware -notoriously favoured over its successors in the later Gameboys by chipheads...