Sylvester Stallone dons the red bandana for a fourth time in this belated sequel that was also co-written and directed by the 60-something star. In contrast to Stallone's bulked-up physique, the plotting is lean: Vietnam veteran John Rambo is sent to civil war-torn Burma to rescue a group of earnest American missionaries who've been kidnapped by government soldiers. Trying to sidestep the embarrassing political legacy of Rambo III (where Stallone's one-man army fought alongside the Mujahidin in Afghanistan), this film spends so little time setting the scene that inattentive viewers might think the hero has returned to Vietnam. The only advancements here are Stallone's age and the use of CGI effects to show limbs being ripped from bodies by high calibre bullets and the odd machete blade. Racist, sadistic and completely in thrall to the thundering fire of heavy weapons, it's a leadenly un-ironic nostalgia piece that belongs to another era.