The only way to enjoy this flick - suspend all belief and take it for what it is...
This is purely a suspend-all-belief, shoot 'em up blast fest, and for those going in thinking it is anything else will be sorely disappointed.
This is a great, end-of-the-work-week goof movie. That's it.
I'm not typically a fan of movies that appear to be based in the real world when it comes to impossible acts of daring-do unless there is some sort of built-in caveat for a character to avoid an endless barrage of machine gun bullets without being hurt - this is one of those flicks. In other words, this is a genre flick like the Expendables series.
So sit back, enjoy the mayhem and ignore the constant whiners on the boards that demand everything be perfect.