Plot hole: When the aliens kidnap the adults, the kids are left behind. But all the kids seen are around 11 and younger. Where are the teenagers or young adults? None of them are during the celebration scene nor in the arena on the alien planet.
Plot hole: There is no way that 'coast of Iceland' could ever have been mistranslated as 'coast of Ireland'. For this to have happened, they would have had to have thought that the 'C' rune was an 'R' rune, but they had already deciphered the word 'coast', so they knew what the 'C' rune was. The 'O's are the same rune and the 'A's are the same rune, plus there is one rune for every letter, so it it's a direct letter-by-letter translation.
Plot hole: When her father is taking the "shortcut" he somehow doesn't need to shift gears even though he has a manual transmission. At the speed he was at he should be in at least 2nd gear.
Plot hole: Summer vacation couldn't be taken away just because it is winter, (or just snowy), they could just go by the date.
Plot hole: When Sully and Mike are talking in the toilets, during Boo and Sully's Hide and Seek game, Boo comes running in screaming and upset because she's just seen Randall, and he's not too far behind since all three can hear him talking offscreen to the CDA before entering the toilets, but how did Boo get to Sully faster than Randall without him seeing her, and how did Randall not hear her screams since they're all in the changing rooms which have an echo?