I finished the entire thing and never had a slow down. It looks like slow motion, as if the animation clock is has slowed down. Weird indeed.

You should try to contact the developers in the forums. It seems that there is something "holding" the performance, like a not well closed while loop unnecessarily running in the background.

chapter 8 is my most favorite chapter because of many things happening :p
I have tried to reproduce that bug but the game is running normal on my machine.

Can you try it with a controller/gamepad?
Sometimes key repetition settings on keyboard affect this kind of performance?

In general there is something wrong with the game on my setup. I used to play it from chapter 1 to chapter 7 without a single issue some time ago.
Now as you can see I have a problem in chapter 8, but it looks like some of the previous chapters suffer as well (but not all of them).
@wolfyrion I use Steam controller, but without it I have the same problem.
Just to avoid other questions - all other games run fine, none of them slow down without a reason ;). And it doesn't matter if I'm in Steam Big Picture or do I launch it from the desktop - it is the same.

I guess I will inform developer, but I have to say that this is a huge let down.

go to LIMBO folder
settings.txt and set backbufferheight = 1080

start the game and let me know if that fix it

Quoting: wolfyriongo to LIMBO folder
settings.txt and set backbufferheight = 1080

start the game and let me know if that fix it

@wolfyrion thanks, I will try to test if this solves the issue in the evening.

However, I've managed to finish the Limbo by using the same system (Ubuntu 16.04) installed on the external drive (an installation that I did some time ago for testing purpose).

Because of that I wonder - what would be the easiest way to track down what difference in the system caused the problem?
1) Should I list all the installed packages in both systems and list them?
2) Is there any particular configuration that you would start with?

I may add, that on my basic system (the one that does not handle Limbo) I wasn't able to install Dirt 3 on Wine to help someone in other thread. On the second system it worked out of the box.

I had troubles running Limbo from the very start and was able to work around it by setting the system to 60 instead of 120 Hz. Probably not related to your problem, though.

The game runs fine for me. Not sure which chapter I am on, though. I picked it up during the Humble Bundle giveaway.