If you're expecting an experience like Fallout Shelter then don't get this game. There's barely any vault management/maintenance needed, gacha aspect to get dwellers, missions are very much alike Preston... They even butchered the resources in this game. You don't need food to mantain dwellers alive (it's used as level up experience), don't need water (it's used as perk experience) and energy is only needed to build more rooms not to maintain them.
Resuming: It's a big gacha game with not so much online aspect, repetitive missions and lacking resources and vault management.