[sirinsidiator]

Looks fine.

I would not use a constant number of achievements though.
Who knows how many we might get in the future.

Maybe something like this (untested)?

local function ExportTitle(achievementId)
-- your export code here
end
 
for topLevelIndex=1, GetNumAchievementCategories() do
  local _, numSubCategories, numAchievements = GetAchievementCategoryInfo(topLevelIndex)
  for achievementIndex=1, numAchievements  do
    local achievementId = GetAchievementId(topLevelIndex, nil, achievementIndex)
    ExportTitle(achievementId)
  end
  for subCategoryIndex=1, numSubCategories do
    local _, numAchievements = GetAchievementSubCategoryInfo(topLevelIndex, subCategoryIndex)
    for achievementIndex=1, numAchievements  do
      local achievementId = GetAchievementId(topLevelIndex, categoryIndex, achievementIndex)
      ExportTitle(achievementId)
    end
  end
end