Thanks a lot for the nice feedback and your kind words! :)
In the beginning, we have discussed to add some brutal deaths to the game and it stayed. You are probably right, that the falling death might not be necessary (outside of the one falling puzzle) and I could increase the deadly height to 8m or so.
I almost added an arrow pointing up to where the lab level (the white floor) starts, good to know that this would have been right... :D