I'm sorry you've had a bad experience in some instances. The portal system was created to give the player the best view of a puzzle upon load. In addition, we wanted to return the player to a baseline position to avoid the surprisingly unpleasant experience of appearing in a new puzzle with a pipe impaled in your stomach.
I sincerely hope the rest of your experience was enjoyable.
I loved it
I'd have thought you could just draw the new level in place based on where the user is currently standing, but I understand if your preference was to contain the entire level within the available playspace - which would require the user to reset their physical location. I do like how natural it is to walk around without worrying about teleporting.