I seem to be _that_ guy which complains about it every single time -> I'm colour blind (red/green) and the tutorial level was hell! Couldn't see the enemies until they fired...
Love your games, but I have minor UI gripe with this one. I'm colour-blind, and some of transition arrows blend too much into the background so they are hard to see.
Yeah, I messed up on that, the future installments will have outlines on the arrows.