(and a cameo by "Buzz" Aldrin attempts to lend credibility to the idea). *****   But, there are also "realish-world" cameos by Kennedy (eerily good effects work), Nixon and Robert McNamara (not so much), Walter Cronkite  (TV archival footage) and Bill O'Reilly (which negates the credibility factor...a lot).  John Turturro returns, and John Malkovich has