I have spent the last couple of days combing hard through all the current levels and trimming them down wherever possible. Every level is now as compact as I can make it, without making it too easy to stumble upon the solutions. I have also added one new level to the first area. I am still considering new level possibilities for the second area, but it seems unlikely at this stage, so I will soon be moving on to designing levels for the third area!
I have also made numerous visual design improvements, largely based off the playtesting feedback as mentioned in the video log. Many of them can be seen here:
There are now soft shadows which appear directly below all objects (it's high noon, I suppose), mainly to help distinguish where floating buttons are. The camera's perspective and FOV have been adjusted to help the player to see underneath things, and the translucent line that you use to enter the level now remains whilst you are in the level, making it clear how far back the player can move without moving out of the level. There have been other visual tweaks, such as all buttons, exit points and entry lines disappearing after completing a level to reduce visual noise.
I am very much looking forward to getting back into designing levels again!