I'm baffled, some things are just dumb.

Why would the game force you to place your first rooms in such a way that you need to destroy them if you want to, as the game tells you later, optimize space?

Why do fires literally mean nothing but a setback while roaches can literally wipe your vault if you had no luck with weapons (totally random)?

Roaches also seem to scale in strength with the size of the room instead of the vault dwellers' stats, which would explain why 6 people can't handle a rush-gone-wrong in their 3-slots room while a single guy easily manages a 1-slot room invasion.

Why does the game tell you people will come to your vault if you have space enough but it's only a fixed number (meaning that you need to have babies, only implied as an option, until you can build a radio station)?

I wouldn't know, this seemed a fine distraction but there's just too much nonsense in it. I tried rushing my 3x power generator 7 times, starting from 1x% fail chance. Got 7 roaches invasions in a row and my 7-10 level vault dwellers got pwned as fast as my 30-something stimpacks reserve just because of bad luck and [censored] scaling. Does it make any sense that rushing works like it does? A totally random % of failure, if that happens you still have a 50% chance (assumed since it's never mentioned, but being there 2 possible scenarios...) that either nothing happens (fire) or you're facing apocalypse.

Could have called it "Fallout: Slotmachines" if this is intended.

I can't really talk about raiders since they came once, nothing really happened and they never showed again since I upgraded my vault door (gone all the way to level 2 not knowing what to expect but they stopped popping after the first).

I'm thinking of making only single slot rooms in my next playthrough if that ever happens. At least until all my dwellers are well armed which being utterly random will probably be around the time Fallout 6 gets announced.

TL;DR

Fix scalings and tutorials if you want this mobile game to be worth playing.