No less than Martin Scorsese's Hugo, J.J. Abrams' Super 8 is a chapter of a filmmaker's early movie life turned into a genre classic. One night in 1979, some kids in a Rust-Belt town are shooting a movie when a train crashes and something some thing escapes from its boxcar prison. Abrams, a teen-tyro director before hatching the TV series Alias and Lost, has made a tender coming-of-age story disguised as a monster thriller. Super 8 borrows elements from the early films of Steven Spielberg, the J.J. Abrams of his day (and this picture's executive producer). And not just plot devices from Jaws, Close Encounters, The Goonies and especially E.T., but their aching, innocent emotions. Did you ever cry at a boy-meets-girl picture? All right, did you cry when a monster wins? Those are just two of the surprises awaiting you in the year's most terrific mainstream movie. The some-thing you'll feel is the beating heart of J.J. Abrams, Super 8's boy genius.