I have cleared the game, but there seems to be a few loose ends, so I'll ask about them here.

1) I have never found the room with the "8" or "infinity" symbol. It seems to be on the other side of the "E" room, but I couldn't find anything. Can it be reached? 

2) At the end of the infinite maze room, the display showed the "E" with the maze room's symbol and the "four squares" symbol underneath.  What was that hint for?

3) In the "H" (?) room (the part which you first warp into), there's a picture of the "4" and "four squares" symbols. Is this only a hint to the location of the "four squares" switch, or is there more to it?

4) In the "4" room, there's a doorway with "four squares" next to it. Is it possible to go through it?

5) Sometimes, an icon made of several circles appeared right in the middle-bottom of the screen. At first there were 3 or 4, but by the end there were 7 circles. What is it that triggers this, and what causes more circles to appear?

6) In the "L6" room, there's a door beyond the bridge. From what I could gather, there is indeed something beyond it, but the hint I found doesn't correspond to the current puzzle. Could you provide a new hint?

Thanks in advance!