Another Sega coin-op, Wonder Boy was a kind of diaper-clad Super Mario Brothers without the depth or wit. Seven levels of scrolling jumpabout action separates Boy from his main squeeze, Tina, who has been captured by the evil King. Collect the fruits and the magic dolls, and hunt down the extra weapons (a stone mallet and a skateboard being two).
Dodge the manic frogs (have you ever seen a manic frog?), the manic bees and the manic snakes, then do in the manic Ogre at the end of the level. None of the conversions are particularly enjoyable, but if you were once a fan of the coin-op they might have some sentimental value.
Spectrum
Not the pinnacle of Spectrum programming but mildly enjoyable in very mindless sort of way.
Amstrad
Just like the Spectrum version. Ok if you can't handle anything complex today.