In the Encyclopedia, there are some places where Greys are referred to as Dead, notably in the description for the Weak Spawner (PS if that's a WEAK spawner I never want to see a strong spawner...).
Also, it feels a little unpolished to have monsters and items in the bonus objective descriptions referred to by (what I assume is) their internal names rather than their names in the Encyclopedia. For example, "Don't use any TacksPickup" instead of just Tacks, or "Kill all of type GreySlow before all of type GreyWandering" instead of Slow Grey and Wandering Grey.