What makes 80s music different is:
1 Sometimes a lot of effort went in to making music videos. Not necessarily very expensive ones but quirky ones that could be described as 'pop art' like Prefab Sprout's The King of Rock and Roll or Peter Gabriel's Sledgehammer.
2. Atmospheric songrwriting/production, with synthesisers or guitarwork. Whether New Wave or New Romantic, there was often a sincere melancholy and/or sincere positivity to the songs. Some songs like 'Who's Gonna Drive You Home?' by The Cars are thick with sadness. In that respect, it was often a properly 'Gothic' decade in the full sense of the word.
3. The big stars of the 1970s continued to experiment and be very popular in the 1980s e.g. David Bowie, Kate Bush, Peter Gabriel, Paul Weller, Sting. Pink Floyd faltered but 1994's The Division Bell was a great swansong. Generally speaking, the big stars used the spirit of the time, where there were big political personalities, to make 'big music' e.g. Kate Bush's The Big Sky, but there was a new concentration on sounding more fresh and 'new age' and artists like Enya came in to this too.
4. :The La's, The Stone Roses, The Happy Mondays sprang up. The latter 2 bands in particular weren't just aping 60s bands but were creating melds of sounds from the 60s, 70s, from America, and formed in to something very particular to the north west of England.
5. The Eurhythmics.
6. Australian/New Zealand rock - Men at Work's Down Under and Crowded House's Don't Dream It's Over. Things like this were arguably important to creating the early 1990s alternative music scene that featured acts like American band the Spin Doctors. Basically, the mid-1980s brought back hippy types (see point 4).
7. 60s acts charmingly became kind of 'one or two hit 80s wonders' with a re-found pop sensibility- George Harrison - Got My Mind Set On You. Marvin Gaye- Sexual Healing. Dusty Springfield- What Have I Done To Deserve This?