Contains exploits, as discussed. Suggestions for improvement (and things to think about when creating puzzles):
> Between the first and second rooms, add a fizzler. This prevents the cube from being brought across into the next area. Fizzlers are excellent for separating rooms like that.
> In the second area, as noted, I did not need the hard light shield nor the rail platform, I highly recommend eliminating all of the portalable surfaces in that area. For pretty much the same reason, I only needed the redirection cube.
> The third area is fine, though there is a minor trapping issue if the player ever decides to walk through the flip panels and they time out. A good solution would be to have the player traverse through a fizzler back up to the starting area. This is a not uncommon technique for ensuring that the player never gets trapped (it gets better in Hammer, where you can use triggers instead).