Yes, on the new demo.
I could shoot but couldn't get any further, evidently I'm missing something, I'll try again :)
That's what I mean about the helmet. You can't survive without the helmet, however if you miss it (because you're rushing to get away from the meltdown) then you can't go back and get it. The door locks behind you So you're locked in a situation which you can't survive.
It would be better to require the player to get the helmet before going outside. If not, then at least don't lock the door behind the player so they can go back and get the helmet.
Think of how Super Metroid handles the suits - sure, you can go into the lava without the Varia suit, but you can always go back and get it. You can enter Maridia without the Gravity suit, but you can't get very far, and you can always go back and get it.