I wanted to just squidge the hell out of his little tummy every time I saw it.

I think they might have wanted to give the ending that first movie feel, but leave it open to further movies. It kinda rang of them not knowing how to wrap it up given those parameters.

Eep, though if there is another movie, I fear for Marta. Unless Aaron stages her death for her safety ala Ethan Hunt in Mission Impossible, the easiest thing they could do would be another revenge movie.