Are you a masochist? Do you like to be punished by brutally hard games? Then you'll like the aptly named Abuse. Abuse is essentially a sidescrolling shooter/platformer trying to be a first person shooter. If that sounds like a contradiction, let me explain.
In abuse, you move your character with the arrow keys. Left runs left, right runs right, up jumps, down activates ingame buttons. However, you control aiming independently using the mouse. This is what made Abuse innovative for its time.
Nowadays plenty of 2D games control that way. Terraria, for example. But back then, applying mouselook to a sidescroller was really innovative. Everything else about it is cool, but generic. You're a space marine fighting aliens.
By aliens I mean xenomorphs specifically, down to a T. They weren't shy about their influences. Still, the unprecedented freedom of independent movement and aiming control makes action faster and more frenetic than more traditionally designed DOS platformer/shooters, like Duke Nukem II for example.
I give Abuse a 7/10. It's very well designed and innovative but thematically very derivative. It's like any generic techbase aliens vs space marines fps on the Android store today, but demade for DOS.
Stay Cozy!