Complex sentence: Oddball's tanks battle their way through the German lines, but their route is blocked when the last river bridge they need to cross is blown up by Allied fighter-bombers, forcing Oddball to let a bridging unit in on the caper.
Split into simpler sentences: Oddball's tanks fight their way through the German lines, but their route is blocked when the bridge they need to cross is blown up by Allied fighter-bombers. This forces Oddball to let a bridging unit in on the caper.