Abyss is described as an unusual adventure game, requiring you to undertake a succession of mental tasks, aptitude tests and arcade games. To achieve your goal, which is to get to the end of the trail, you must complete every test correctly. The tests are randomised as to type and difficulty so you can be lucky and have a succession of the easier tests.
However, to achieve your goal you will have to prove your intellectual prowess and be able to get the more difficult tests right as well. After each test you return to the matrix and proceed to the next stage. To reach the following step you have to cross over rickety bridges. If you're unlucky the bridge will fail and you will be plunged into the abyss.
It is a game for one player, the rules are simple and no problems were experienced in loading. The front of the cassette is labelled CCS adventure games, but to my mind this not really an adventure game.
As an adventure freak I was bound to dislike this program, since I had obviously expected an adventure. However having said that I could find no technical fault with it. It's a capable program, but not the adventure it purports to be, being more of a quiz than anything else.