Excel is probably for reporting linguistic problems.
Reader is probably for reading the original language text and the localized text.
Of course, you also need to be able to play the game and see the text in context, which means you may need to demonstrate that you're a good game player in their particular genre.
And you have to demonstrate the ability to communicate problems clearly.
You might want to read http://www.sloperama.com/advice/lesson5.htm