I was watching Youtube yesterday, and someone was playing a DLC for Amnesia. Didn't know about it.
In case you own Amnesia (on Steam), you can acces the DLC (it's free) through the launcher menu. It's the 3th button named Justine.
So, apparently it's made by Valve, so no wonder it has some links to portal. Also, the thing that makes this game very difficult is that when you die, it's game over and you have to start all over again.
Not going to spoil, so try it out and let us hear what you think about it
I also just found out that the more people that play it, the sooner Portal 2 will get released