Short answer
The useful part first.
Final Ascent adds 10 new badges and matching cosmetics. The official Steam store now lists 64 total achievements. That count is verified; a complete step-by-step unlock guide is not yet published here because several new conditions are tied to hidden discoveries.
The verified numbers
Why do some older lists show 54?
Those lists reflect PEAK before the Final Ascent batch. The update added ten badges, while the live Steam store now reports 64 achievements. Check the page date before following an older checklist.
Where are the unlock steps?
The official patch announces the batch but does not publish a complete walkthrough. Some requirements involve content the developers intentionally left secret. A useful unlock guide needs the exact badge text, reproducible conditions, version confirmation, and—where location or puzzle steps matter—visual evidence.
How to verify your own list
Open PEAK’s Steam achievements page while signed in and compare it with your in-game sash. Steam is the best current source for the live count; the patch notes establish that the ten additions belong to Final Ascent. If the two views disagree after an update, restart Steam before assuming a badge was removed.