Unreal Tournament III

This trophy is awarded for simply completing 10 campaign missions in co-op. Assuming you are doing this in splitscreen with a second controller, just play on casual and it shouldn't make much difference that you are down a teammate. If you don’t want to make a backup save before defeating Akasha on Insane then you can run through that chapter again to get most of the missions done and get Thanks to All the Little People, then just replay another chapter until you get the trophy. If you did reload a save to defeat Akasha first, then simply play through whichever chapter(s) you liked the most until the trophy pops.