The Secret of Zinj is an unreleased tie-in of the movie Congo. The game features many different gameplay styles, running the gamut from shooting enemies in first person à la Operation Wolf to canoeing. The problem is, they are all badly designed and very frustrating, in part because the graphic engine seems unfinished. The game was probably cancelled because of development issues and the fact that the Snes was at the end of his life.
You can find more info on this game on SNES Central!