The Black Lagoon
By L&M Software
Tape 2, 1981.

You have accepted a dare (after much prodding of course) to pilot a boat (by using joy stick 1) through the "Black Lagoon", to a dock on the other side.  This lagoon is no ordinary, run of the mill type, lagoon. It can only be navigated by passing through the interconnecting waterways. Any attempt to pass between sections of the lagoon other than by using the connecting waterway will be blocked.

Each waterway has a pump station, which will come in handy, as the boat which you are to attempt this journey with has a very bad leak and cannot be fixed. Upon arrival at a waterway, by checking your bilge level you will be able to determine whether you need to use the pump station. Should you elect to use the pump station press trigger 1. Your score is then reduced and the creature hearing the pumps will surface and come for you. The location which he surfaces will vary, therefore, varying the time it takes him to reach you, this will determine the time you have to pump down. Just before he reaches you, by pushing the joy stick to the right you can enter the next section of the lagoon and temporarily escape the creature. 

The creature is constantly roaming the depths of the lagoon unseen by human eyes. Should you happen to be at the same place he is or if you allow your bilge level to reach "full", causing you to sink, the creature will capture you. The "Black Lagoon", also, has the mysterious capability to change shape and to change the location of the waterways and dock with each new attempt.