Implementing separate locked/unlocked faces on js2

That code looks correct except for setTimeout(0); which does nothing I think.

I havn't used images so I wonder if reading them is too slow here. You could try code like this instead so you read images once when app starts and not every time it's drawn (this code is replacement for your daylight function):

var faceDaylight = require("Storage").read("FaceDaylight.gif");
var hourHandDay = require("Storage").read("HourHandDay.gif");
var minHandDay = require("Storage").read("MinHandDay.gif");
var secHandDay = require("Storage").read("SecHandDay.gif");

function daylight() {
  var d = new Date();
  var h = d.getHours() % 12 || 12;
  //var time = (""+h).substr(-2) + ":" + ("0"+m).substr(-2);
  var HoursAngle   = (d.getHours()+(d.getMinutes()/60))/12 * twoPi - Pi;
  var MinutesAngle = (d.getMinutes()/60) * twoPi - Pi;
  //var SecondsAngle = (d.getSeconds()/60) * twoPi - Pi;
  var SecondsAngle = (d.getSeconds()/60+d.getMilliseconds()/60000) * twoPi - Pi;
  g.reset();
  g.clear();
  g.drawImage(faceDaylight);
  //DateWindow
  g.setFont("6x8");
  g.setFontAlign(0,0);
  g.setColor(0,0,0);
  g.drawString(d.toISOString().substr(8,2), 138, 88, 0);
  g.drawString(d.toISOString().substr(8,2), 139, 88, 0);
  g.drawImage(hourHandDay,xc,yc,{scale:1,rotate:HoursAngle});
  g.drawImage(minHandDay,xc,yc,{scale:1,rotate:MinutesAngle});
  g.drawImage(secHandDay,xc,yc,{scale:1,rotate:SecondsAngle});
  queueDraw();
}

And similar change for nightglow function.