I just thought this was something that'd be nice to have in SMBC since it has all this great music. For one thing, it'd be helpful for keeping track of what music everyone has -- I keep worrying as I play that I'm missing out on some of the music because I'm not playing the right map skin or something. The way I see it, you'd pick a character and a skin, and a list of "themes" would come up -- Overworld, Underground, Athletic, Castle, etc. -- and you'd pick one, and it would play the song associated with that theme for that character and skin. For example, you could select Mega Man, 16-bit Mega Man, and Overworld Night, and the Robot Master Museum theme would play. In most games, the sound test has some really rigorous condition to unlock it, so I guess we should do the same here. The most obvious one -- beat the game on Very Hard -- is already taken by Level Select, and I think it deserves that condition more than Sound Test would. So, I don't really know what the condition would be. One that would make sense is "hear every song in the game", but actually doing that would be a huge hassle that nobody deserves. Obviously, this request comes with the same caveat that all of mine do: If this would take an inordinate amount of time and effort to pull off, then just forget about it. I still don't know what's easy or hard to do in Flash, except that it doesn't make any sense.