Random something I never understood about portal (that this reminded me of): if you jumped into a portal feet-first, wouldn't you come out the other side feet-first as well? Your feet are always facing the ground in that game no matter what, but if you put both portals on the floor and jumped into one, realistically you should come out of the other side upside-down.
But enough of that crap. This is a really funny flash. The duck hunt part was probably my favorite :]