Yeah I'm an engineer and I came to terms with the fact that most of the science in this movie is hand wavey. That's ok! It's not a movie about technology, it's a movie about mystery.

The napkin of course doesn't even try to make sense, they never even explain what the central idea of Alpha is. The fact that hydrogen gas would leak out of residential natural gas lines is a known problem, but it's an easily solvable problem for a spacecraft or a power plant. In fact a breakthrough in hydrogen tech would be world changing if you just plan for it the right way. Like was said above, the case opens and closes based on when the plot needs it to. The robot dog carrying the luggage was a gag but how did it load and unload the luggage? The fire extinguishing system conveniently came on only once it was too late for the plot.

And again, I don't mind any of this. It's a good movie which isn't about technology, it doesn't need the tech to make sense.