So this is completely mysterious. I wrote my own postscript EPR runner, and that one works just fine (see below) (could arguably be cleaner with the dicts and things, but my point is more that it displays all pages). I am completely baffled why the commandline with the Artifex built-ins doesn't work.
L > gs -sDEVICE=pdfwrite -o combined.pdf -dNOSAFER test.ps test.ps below %!PS /BeginEPSF { %def /b4_Inc_state save def % Save state for cleanup /dict_count countdictstack def % Count objects on dict stack /op_count count 1 sub def % Count objects on operand stack userdict begin % Push userdict on dict stack /showpage { } def % Redefine showpage, { } = null proc 0 setgray 0 setlinecap % Prepare graphics state 1 setlinewidth 0 setlinejoin 10 setmiterlimit [ ] 0 setdash newpath false setoverprint } bind def /EndEPSF { %def count op_count sub {pop} repeat % Clean up stacks countdictstack dict_count sub {end} repeat b4_Inc_state restore } bind def /RunEPS { % epsname llx lly urx ury /ury exch def /urx exch def /lly exch def /llx exch def /epsname exch def BeginEPSF urx llx sub /w exch def ury lly sub /h exch def << /PageSize [ w h ] >> setpagedevice llx neg lly neg translate epsname run showpage EndEPSF } bind def (whole-note-tremolo-accidentals.eps) -9 -339 357 0 RunEPS (warn-expected-warning-missing-1.eps) -9 -37 58 1 RunEPS (woodwind-diagrams-ring-keys.eps) -9 7 19 87 RunEPS (volta-spec-ossia-1.eps) -9 -89 123 0 RunEPS (typography-demo-1.eps) -9 -814 497 -49 RunEPS (tuplet-number-alignment-1.eps) -9 -51 118 0 RunEPS (trill-spanner-grace-1.eps) -9 -41 102 0 RunEPS quit -- Luca Fascione