Maybe people were confused what it was going to be about

Battleship director says he's finally figured out why it was a massive flop

http://www.blastr.com/2013-8-19/battleship-director-says-hes-finally-figured-out-why-it-was-massive-flop

Amazingly, the answer STILL isn't "Turns out nobody was even a little bit interested in seeing it."

No. Dude sez it was lack of star power. Cuz, yeah... Liam Neeson in an action flick in early 2012 was slappin' together a real indie no-name kinda cast.