But Mission: ImpossibleDead Reckoning Part One (Paramount, 7.12) is totally wowser — a shot of grade-A adrenalin and nothing but breathtaking elements top to bottom, plus some of the action sequences struck me — this was surprising — as almost Buster Keaton-ish in a welcome way. But the Austrian train wreck finale is in a knock-your-socks-off category by itself — an INSTANT CLASSIC.