REXLOAD.stc from Rex game intro
Seems, UNTRUCT.pt2 is prereleased version of music in Spirius demo
Spirius Demo (without RRD).ay is special version for Ay_Emul v2.9 and older. Spirius Demo.ay uses RRD Z80 opcode, which is emulated incorrectly in theese Ay_Emul versions.
1ST.pt2 found at ISAY6\DEMO\BADBAD.TRD of AAA collection with Tula musicians music (can be by other author)
