Gainax Ending: After following a fairly clear-cut routine plot, the film's ending is... open for interpretation, if one wants to be generous. Matt and Isabel are last seen staring at each other in the helicopter back to the US. It's completely unclear what the future has in store for Isabel, and if she will recover from her massive mental trauma. Matt's fate is just as open after he disobeyed a direct order. Worst of all, after the last we saw of Alejandro was him being barely able to walk, what with the gunshot wound in his head, he's suddenly back in the US and as fit as ever after the one-year Time Skip. No explanation is given as to how he accomplished that, who helped him, who he's currently allied with, and what plans he has for Miguel.
I don't think just having an open-ending conclusion qualifies as a Gainax Ending.
Removed:
I don't think just having an open-ending conclusion qualifies as a Gainax Ending.