The house containment and suits
Ok this whole bit is hilarious. First of all do they want the entire world knowing they have something? Way to be discrete guys! Why try and make all these containment rooms in the house. It would have been easier and better to simply remove the alien and the family.
And first off what was up with the full on astronaut suits?! The first few that come in look ready to go to the moon. That was hilarious and ridiculous. Then in the next scene people have all this simple gear but to look like full contamination suits on but with simple little plastic flaps for their heads with hoses running underneath and then wait for it. Totally exposed skin at the wrists and arms between their sleeves and basic latex gloves. Oye.
Then as soon as ET "dies". They rip everything off and tear down all the containment. How stupid.
I mean it's a cute enough movie especially back in the 80s. But this was just odd.