Complete video walkthrough + all achievements.
There are 8 achievements awarded for completing the 7 chapters of the game.
Walkthrough + Speedruns
There are 7 achievements tied to speedrunning the chapters of the game. When you first enter a new chapter, Save. Then, if you fail an attempt, Load the chapter and then Restart the chapter to try again.
This video shows how to complete the full game, and does each chapter fast enough for the speedrun achievements. I found 2, 3, and 4 to be the hardest, taking about 3 tries each, while I got 1, 5, 6, and 7 on my first try.
In Chapter 7, make sure to take advantage of the warp-to-dome feature, when possible. Also in Chapter 7, the totem pieces are not random, so write them down or memorize them.
- Garden: 0:00
- Maquette: 2:50
- Gateways: 6:58
- Wedge: 11:31
- Escape: 21:00
- Spiral: 24:58
- Exchange: 31:12
There are 3 achievements that are not story, but not missable: Open Sesame, Size Manipulator, and Precise Placement. You should earn all 3 of these by Chapter 2 at the latest.
That leaves 4 actually missable achievements:
- Breakout - Go over the wall in Chapter 2, The Maquette. Use the key and prop it on the diagonal of the mini-Castle, then walk up the diagonal key in the normal-Castle and jump over the wall.
- Crew Creatures - In Chapter 3, Gateways, near the very end, after you've used the Red Sphere to break down the very large wall/barrier, walk as a tiny person to the Green side, and go through a crack in the wall. Continue walking and enter the Dog House.
- Into the Darkness - In Chapter 6, The Spiral, walk off an edge / commit suicide.
- Run, Move, Run - In Chapter 7, The Exchange, the 2nd lever you pull will create a bunch of arches and require you to race across to a timed door on the other side. Make it into the timed door on your first pull of the lever. If you are worried about this, save right before pulling the lever and re-load your save if you fail. [You will also almost certainly get this when doing the Chapter 7 speedrun].