Redesigning a set of 25 smiley faces that vary on 2 dimensions (Pleasantness and Energy)

This is what Decision Lab was looking for in their graphic design

I need to redesign a set of 25 smiley faces that I use in my research to measure how people feel along two dimensions: Pleasantness (from Unhappy to Happy) and Arousal (from Low Energy to High energy). I've attached the current set that I use. It does an OK job at depicting the two dimensions of emotions (Pleasantness and Energy) but I find it quite ugly. For inspiration, I've also attached smiley face designs that I find more appealing. Thanks! Read more