On Windows Build, v 1.01 x64bit, I've find out that setting up a graphic configuration that increase or decrease the average fps results in a sensible variation in the character walk speed. You can verify it, in that puzzle at the beginning of the third session where there is a big red floor that you have to make emerge from the wall on your left and you have to use as a bridge to reach the passage to the next area. For me, reducing of an half the render scale (from 100% to 50%), with all other graphical properties setted at their lowest value, (screen resolustion = 1024x768), the fps increase from 15-20 to 40-70: with the first one the walk speed is so low that it's impossible to cross the bridge in time (really, I've tried many many times but I can walk only up to 2/3 of the "bridge" and a last jump is useless), while with the second one I crossed it easly and rapidly. I suspect that it's something related with the combination of the floor movement, the walking and the presence of many light on both sides fo the floor that require an higer elaboration time, in fact with the configuration that lowered the fps, untill I don't start that animation and I only walk in the room, fps it's around 20 but it drops to 14-15 when floor moves and I walk on it.
Thanks anyway for the attentions and your work.