The obvious signified of a flashback is to do the art in black and white.  That gray shading I add in there is an effect I wish I had time to do on all the SuperFogeys strips.  Plans are for that effect to be added to the strips for the trade collections.  Once that happens, the strip will finally look the way I want it to.
But these flashbacks?  They are just how I want them to look.
Spy Gal’s isolation at the end makes me sad.  You just know what’s coming.  Weird angle for me to draw.  Generally, I’m not good with weird angles.