Gantz is a live action adaptation of a rather bonkers manga/anime about a bunch of peeps snatched at the moment of death to fight against aliens at the whim of one spherical Gantz, a cybernetic arms dealer cum ringmaster. Anyways it's one of the better anime to cinema ventures, certainly better than Mushashi and from what I can remember it follows quite closely the first 6 or so episodes. It's also blessed with a better than average teenage cast and a certain gusto when it comes to gorier side of alien vs human battling with plenty of headpopping, disemboweling and blood letting. Sure it's not the most sophisticated of scifi films and it's got a touch of Japanese strangeness (and cheese) to it but it's a action packed spin on the usual invasion story and I'll be keeping an eye out for the sequels.
While Japan might be able to thwart the usual Alien attack tropes Battle: Los Angeles doesn't even try and treads much more familiar ground with a semi-shaky-cam movie about the Military response to a massive, aggressive alien invasion of the US of A. Anyways Eckhart and co grimace and yell their way through the thinly drawn stereotypes as they spray the Invaders with bullets in a seemingly futile resistance with the usual dwindling numbers, but lo! our hero via a series of miraculous coincidences seems to save the day. The action is pretty good and it's a reasonable enough watch but ultimately this is as B-movie ish as Starship Troopers but lacks the social satire or tongue in cheek laughs. If it's a success I'd expect sequels.