Interesting, a SSEQ player, I guess I will give it a try today
As for all GBA wonders "can it play GBA music"
Nope, GBA uses way diffrent stuff, NDS is compatible backwards with GBA music by Z80 chip "inside" of ARM7 but it doesn't make those two being "same" for music part
However if someone wants to play GBA music without turning on specific game, there is a way, not best one to be honest but IS
It's about program that can "unpack" (note the quote mark) music from GBA games to MIDI format, this MIDI file can be played "as it is" but of course will sound a bit diffrent, so next step would be to import it to Tracker program, edit the instruments for GBA looking and voila, however the noise part can be problematic, I myself didn't found the perfect way how to set-up noise to sound like GBA one