In demo mode there is only WASD. Is it possible in the full version to rebind keys to arrows ?

does this game use raytracing?

I‘ve found all of the cylinders and gotten the mirror gun, but I have no idea to find the hidden gallery in achievement, please give some hints. Thanks.

the other difficult puzzles at least took me under a day to figure out. this one is just, absurd its the one with a blue orb, a large gap that you have to cross with the key, and a diagonal facing mirror on a big cyan block any help with this puzzle would be enormously appreciated...

I'm having trouble understanding how gravity changes when I go through the diagonal mirrors. Anyone has an easy explanation for it? I have been going through the game not fully understanding it and now I'm stuck at a part where there is 1 diagonal mirror and 3 movable mirrors on yellow puzzles....