I wasn't expecting it to be this good, considering that I got it for free on GOG. If you liked Portal, I am pretty sure that you'll like this game too.
Graphic wise, it's using the Unreal engine, as such it's quite impressive (even for 2016). Music is acceptable. Story meh, could have been better, but the sound acting is very good. Anyway it's strong point is the gameplay, which has quite inventive puzzles to be honest.
The only thing that I can think of negative, is that magnetism doesn't actually work like that... but it isn't a big deal...
All in all, I think it's a quite enjoyable game where you don't need to just spam the "shoot" button, but you get to use your brain a bit :)