Quick answer: A full completion pass is easier when you separate main progression, optional puzzles, transport unlocks and post-game cleanup into one visible list.
Main progression
Opening Drawbridge route; map progression; colored tower systems; main ending route.
World systems
Train, chairlift and tunnel access; map landmarks and coordinate clues; useful items and communication tools.
Post-game cleanup
Purple puzzles; platform achievements; collectibles; any optional activity your group chose to track. Record what is confirmed rather than relying on memory.
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.