I don't think I can really adequately describe how much sound you can get out of a pair of Game Boys. Just know that it's a lot and you should listen to this if you like chiptunes at all.
This is a fantastic combo duo, too. I was initially attracted to this one because I know Zef makes really good work tunes; I was peripherally aware of Danimal Cannon from DoD, but I didn't realise he worked in PSG too! I do now.