Well if we're talking the 16 bit versions, fast moving mainly vertically scrolling cross between Football and Rollerball.
Very violent. You attain money by victory and you can play dirty...in fact its encouraged.
And with your credits you buy upgrades for your team (Speed, stamina, defence, strength, offense etc) and options to play 1up vs 2up, league, one off matches, and other options.
Bastard well addictive and was one of the best 2 player games of the nineties. (Speedball 2, that is....Speedball 1 was kinda "alright" but nowhere near the sheer genius of SB2) Still great fun to play. 🙂