18 9 2Actions Report Solution To unlock this, simply complete 10 codex entries, these are the little challenges scattered across each mission in the game.Showing both comments. Leave a comment. it seems that collecting the field manuals challenges don't count for this.Posted by imoneoldfart on 10 Nov 18 at 05:11 No it doesn't as they are a standard challenge for every mission it is only the mission specific challenges that count.Posted by ElliotStone on 10 Nov 18 at 13:12 Leave a comment