Keyboard: arrows = D-pad, X/Z = A/B,
S/A = X/Y, Q/W = L/R,
Enter = Start, Right Shift = Select. Select a
.sfc / .smc ROM above to begin — audio starts on
the same click (browser autoplay policy). This is the same menu-bar shell
the native binary uses, including Settings… (theme, key rebinding, speed
presets). One browser-specific gap: the Save States manager has no
filesystem to write to here, so slots don't persist — use the native
build for that.