I remember discovering The Catacomb Abyss by a magazine coverdisk, a few months after the release of Wolfenstein 3d. Even then, Abyss was starting to show its age. That said, I enjoyed the coverdisk version enough to eventually upgrade to the 3-episode registered version, as there's a surprisingly fun little game here, with more interesting environments and enemies than Wolf3d. Playing it again today, I suspect it hasn't aged tremendously well. I'd forgotten how heavily the gameplay is hinged around key-hunting, with finding not only secret areas, but secret areas within secret areas becoming mandatory pretty quickly. Still, it's worth a try if you want to see one of the very early stages in the evolution of the fps as a genre.
