You have been locked in a prison where illegal genetic experiments have been going on. The scientist figure out how to genetically make anyone go into a rage. They call it the Abuse virus. It has gotten loose and spread through out the entire prison. You have to fight your way through all the mutated and enraged enemies and make sure this doesn't leave the prison.
This is a great game, period. It was awesome when it came out in 1997, it is still awesome today.
Think of an sci-fi fps game with aliens, now put it into 2 dimensions - boom, you got Abuse. This is not a platformer in a traditional sense as it may seem from the screenshots, this is mainly a shooter.
The skill level is rather high compared with todays games, nevertheless it's loads of fun for a seasoned gamer.