I could make the door, maybe if I had any time left.
Here's the Weighted cubes, they have already been made
(You cannot pick them up with the portal gun in a minigame)
Give the player both the Portal Gun and the Gravity Gun.
Please don't, I'm working on a content pack come-back with this in it
In a minigame equip the portal gun and press L i know its the light key but while holding the portal gun its the gravity gun key.
... *rant* I know this aready but...