Quick answer: Purple puzzles belong to the post-game cleanup route. Keep this page for after your group has reached the main ending or consciously opted into spoilers.
When to start
Complete the main route first. Post-game challenges work best when the regular host save and the players who want to finish them are available.
How to track them
List each discovered purple challenge; record its region and the original mechanic it remixes; mark progress as a group rather than assuming every player has the same memory.
Cleanup advice
Use unlocked transport to reduce backtracking; finish one map region at a time; compare your list with the 100% completion checklist before revisiting the final area.
Source & update note
Core platform, player-count, crossplay and hosting facts are checked against the official Big Walk FAQ. This page uses spoiler-aware community route notes and should be rechecked after game updates.