THE ANSWER
The official achievement list identifies five campaign acts, co-op completion, secondary objectives, Hard Cases, collectibles and an Insane-difficulty completion goal. You can track those goals now without needing an unverified route.
A personal record, not a game-account sync
The companion provides manually checked campaign milestones. Mark a category only after you have met its full requirement in the game. Five checked acts represent act milestones, not 100% of all achievements.
The published requirements do not establish item counts, item locations, missability or replay rules. We have not filled those gaps with guesses.
Keep your first playthrough yours
Kingy preparation advice · not a tested gameplay procedure
The official full list includes story-related achievement names. Our checklist uses neutral act labels and objective categories instead.
If you want to explore blind, save the checklist for later. If you want to pursue completion, note where you stopped and which objective category you still need to verify.