If you thought that this one had fewer colors, you'd be right. I can take most comics, set them at 256 indexed colors, and still get them under 200kb. But THIS one, for some reason, insisted on being a little more difficult.
Wow, you must have sharp eyes. I increased the brightness on the previous comic by about 15 points, but I figured this one didn't need it. Partly because I had to redo the backgrounds and the ambient lighting in each panel.