1) They dont tell these civilian soldiers the enemies weakness (Belly) and provide them with largely ineffective weaponry (They could have utilized additional weapons that would have had actual effect and provided them with more firepower) and with no training at all let alone any sorta leadership structure
2) Another weakness appeared to be fire as Queen ran from it. Why are flamethrowers not being utilized against Aliens?
3) WTF did they not kill queen in lab with guns , etc when attack was underway. Instead they just leave her to be freed
4) The walls surrounding are were not manned with soldiers ,, Seriously why would they have not had machine guns , emplacements , etc in place.. Mines and Helicopters was piss poor defense strategy
5) The ending was so f***ing dumb... You have the serum to kill females so why not have governments of world produce it and stockpile it for day the aliens show up and attack humanity? The future is saved right there
6) Why would government who put resources/$ into helping war in future just say "We dont care to look for the aliens being on earth , etc.. You would think it would be incentive to actively investigate if they believe the war in future has been lost
7) Also why would NATO disband suddenly just because link to future is severed? Why would world just give up? They would have decades to plan and prepare for war which is something the future Humans did not have.. So dumb
8) The ending again with f***ing kid , annoying guy , etc in Russia was so dumb and WTF did he mean "We dont have time for UN to argue , etc after finding ship"... You have decades of time actually before war to get shit done
9) JK Simmons entire role was pointless and a waste of great actor