They recycled a character model from their previous work.

I thought he looked familiar. Pretty cool. I remember square enix talking about "digital actors" way back. Before the spirits within bombed they wanted to use the main girl in different unrelated films.

That's it! I remember watching Starship Troopers invasion thinking "where do I know him from?" racked my brains until suddenly this came into my head. I thought Varro was based on an actual actor which is why he looked so familiar. But hardly surprising they use the same character model when both Starship and Appleseed have the same director.