Mastertronic Plus is, as you might have cottoned on by now, the label that Mastertronic uses to re-run old full price games at budget price. This kind of equates to hardbacks and paperback in the book world. Titles come out in hardback (full price) then afterwards get released in paperback (budget).
Back in 1985, Activision released this one - a boxing game endorsed by the then famous plucky Irish boxer Barry McGuigan. Both the endorsement and the product have faded a little with time, but if you want a competent cheapie sports sim, with a higher than average strategy bit, then come out fighting to get this one.
Spectrum
An excellent boxing game which provides plenty of thrills and spills. Excellent graphics and gameplay.