A revolutionary control scheme stuck in an otherwise unremarkable Doom derivative shooter. Like many shooters coming out in the early 90s, it suffered from jumping around engines during development as a result of the quick advancements id Software was making with Wolfenstein 3D and then Doom. Raven had the good sense to move on from the ShadowCaster engine and implemented a mouse-look mechanic that allowed you freely aim your gun on the screen. It also incorporated elments of interacting with the HUD and the world via the mouse which would later be developed further by games like System Shock, Deus Ex, and pretty much every FPS RPG to come after. An unsung hero of the early days of the FPS.