How does this walkthrough work?
The guide follows the game's actual progression from Liz's login screen through the final tribute puzzle. Each puzzle starts with a light hint, so you can keep solving on your own before revealing the answer. Jump by what you see in the game if you don't know the step number, or use the contents list to open a specific room.
How long is Last Seen Online?
A straight run is about thirty minutes. Reading every chat, note, and photo takes longer. Essential keeps the required path. Completionist flags extra looking-around that is not needed to reach the ending.
Does Last Seen Online have missable content?
The main puzzles are required to finish. Buddy List conversations, diary notes, extra photos, and several achievements are optional. You can finish without reading everything on Liz’s computer.
Can I use this guide without spoilers?
Yes. Hints come first, and answers stay folded until you reveal them. Quick Answers is a separate full-spoiler view for return visits; it asks before it opens.