I recently completed a playthrough of Abuse. I remember it from my childhood as insanely hard, but actually I found it quite enjoyable.

Good parts: soundtrack, interesting puzzles, lots of save points so pick it up/put it down when needed, some of the weapons are really cool, ran perfectly on dosbox, artwork was nice.

Bad parts: no storyline, gameplay became a bit formulaic, end boss was disappointing, a couple of really boring parts looking for a switch or hidden door.