I write and edit both for video-game companies and for my own games.
I contributed to the dialog and backstory for two heroes in Dota2, a Valve game. One of them is Medusa; her dialog is here:
You can click on the “play” button to the left of each line to hear the dialog performed by Jen Taylor, with some lovely and eerie post-processing.
And here’s Medusa’s backstory:
I also edited most of the dialog for Halo 4 while I was working at 343 Industries.