They could have shown the entities at least once.
The five year time skip was not realistic.
When Charlie was rambling about pregnant women birthing monsters I thought that would be a key plot point, but it wasn't explored.
The white guy Olympia let in, why did it take so long for him to turn when it was instant with everyone else?
It wasn't terrible but it had a lot plot holes and it's not like the film wasn't long enough to give us answers

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