4th Dimension/Hewson (YS52, 52)    A four-pack of unreleased games that don't compare well with the rest of Hewson's achievements. Rock 'n' Roll/Rainbow Arts (YS50, 74)    Persevere with the unglossy look and there's lots here to do and see, even though it is in yellow. Sporting Triangles/CDS (YS48, 40)    Thirty minutes of yawnsome TV successfully converted into the same amount of game playing time. Sport triv nutters might want it though. Xenophobe/MicroStyle (YS48, 76)    Fans of the coin-op will find this tasty, authentic conversion fills the gap. The enjoyment of everyone else will probably be short term. SAM Surgeon - MGT's Demise (YS56)     So what really has happened to the SAM Coupe?