This is apparently the last Gygax module for AD&D, and it is larger than early modules at 48 pages. Unfortunately, it suffers from some poor editing (confusing stats for giant carnivorous apes, unclear number of mezzodaemons, etc) and additionally some of the "massed tribesmen" encounters could take forever to resolve. It seems a little more "fair" than Tomb of Horrors but there are plenty of chances to "instantly kill" high level characters in this module, and there's a fair likelihood of the party either ending up trapped, TPKd, or having to trek the island for weeks/months of random encounters before finding the exit. Bring your clerics (plural) and enough spell components to resurrect, and you might be able to finish this. In any case, I doubt most players would want to try this module today (upconverted or not).
Typical Gygax. Ridiculously unnecessary detail at some points. Total asshole pomposity about being a DM...setting up “DM vs player” personality conflicts.
Completely confused terminology about “carnivorous ape”, “giant carnivorous ape” and “gargantuan ape”, to the point that we get conflicting facts about how many are on the island.
Crappy maps and text that doesn’t align with it. And the whole “three witch doctors” bit was unclear and incomplete.
And the story line, especially the ending, is convoluted and somewhat stupid.
All in all, a mediocre effort AT BEST.
As an adult I see all the flaws of Gygax that were hidden behind the blind hero worship I had for the man when I was a boy.