I thought Knowing was a cheesy hack job, but that's just me I guess. Predictable, dramatic high points marred by over acting, no sense of humor about itself. If you like the premise I recommend this instead.
Anyway, giant robots > aliens.
I don't blame Cage's performance though, I mean he can play a depressed drunk very convincingly. It's more a case of that truism 'never work with kids or animals'.
I much prefered trees going apesh.it.