I think most of those are in the works. I dunno about changing the interface, but once the source is released there's nothing stopping us from doing that ourselves. Also, [Clear] worked for me. [Vars] might work, too, just because it's the same value as [Clear]. If [Vars] is stopping it, then other keys in that row ([Math], [Prgm], etc.) should stop the player, too.

Also, since the 82/83 version don't support external files, i think it'd make more sense to wait until the main engine is a little more developed/closer to its final state, that way you don't have to worry so much about keeping track 2 different engines or filling your code with conditional code à la Phoenix Anyway, i have a feeling the programs will be written for the 82 then ported to the 83/+ afterwards. But i agree, external files for songs would be nice. As it is, the songs are stored in the program itself, so if you want to share you'll just have to transfer the entire program over.