How bad is it? Completely generic action without direction.
Should you see it? No.
The director of the second film in the series returns and Todd Jensen plays a third character, but no one else returns for this last installment and it has no real connection to the previous films. Delta Force tries to rescue an ambassador, but men get left behind to be turned into suicide bombers through mind control. Now they have to be rescued before they act (the ambassador is forgotten). There's plenty of slo-mo, plot holes everywhere, continuity errors (the number of people on screen changes between shots and Boston has palm trees), bad acting and inane dialogue. There's only one good action shot, where a plane crashes into a train. This is incredibly generic: any character could be any of the others and any location could be anywhere.