'Trinity' dominates with a Carrol-like "Alice in Wonderland" fixation, where you play an American tourist stuck in a giant magical garden with huge mushrooms, secret wizard shacks and ancient tombs. In spite of this mystifying background, the primary objective of the game is to use this garden dimension as a hub world, from which you can leap interdimensionally to various points of real-life history, where each one is concerned in some way with the history of the development and testing of atomic weaponry. (the game itself is named after the
Trinity test of atomic explosions in New Mexico in 1945) Although the game concerns itself with an anti-war and anti-nuclear armament message, the game's puzzles and logic are way too lax on the theme, to the point where any nuclear messages come as superficial: Many of the puzzles in the giant garden are comic and cut out of the indicipherable Zork cloth, and the isolated episodes where you have to involve yourself in key points of nuclear history does not actually involve you to correct history and prevent it: You can't stop the orbiting satelite from being struck by a missile. You can't stop the girl in Hiroshima from dying. All you are asked to do instead is pick a random item from the historical period(which the game itself will never tell you), and just leave discreetly like a casual observer while using the items in any of the future puzzles. You only have one shot in any of these isolated episodes and if you don't do the right things you block yourself out of the endgame forever.
'Trinity' is obtuse and hard, and like most other Infocom games it features puzzles that are easy to screw up, items that are easily missible and lost forever, and where it's very easy to die because of uninformed choices. You can't play 'Trinity' without a walkthrough, and it's hostile to unassuming players, but as such is a great demonstration of the kind of mentality and genre tropes that are always involved in Infocom games. I suppose if you could only play a single Infocom game in your whole life, 'Trinity' wouldn't be a bad choice.
But
A Mind Forever Voyaging is so much more grateful: You can't die in that game, you can't make any irreversible choices(except one at the end), and it's easy to navigate and with a clear purpose of theme. You can beat it without a walkthrough. A Mind Forever Voyaging is a true novel unfolding before your eyes, stimulates your imagination, asking you large questions and where every word bears grave importance, whereas Trinity's lax descriptions and random puzzles would not be out of place for any Zork game. Trinity does not commit to a concrete form but is all over the place, unlike many earlier Infocom games that had creative premises and worlds(but also difficult gameplay):
Hitchiker is a brilliant and accurate game adaptation of a famous comedy novel,
Deadline is its time-stressful detective game where you have to figure out a murder case,
Starcross concerns itself with the delicate but lush and multiplanar ecosystem within a space colony,
Suspended is about controlling robotic functions while in cryogenic sleep, and
Wishbringer is a juvenile, 1980s Steven Spielberg suburban kid fantasy adventure brought to video game form. That's not to say that Trinity is not as vibrant as any of these other worlds(and has very captivating introductory and closing sequences which are the only times it truly comes alive), but compared to them I think that Trinity's uniqueness is a little overstated and too unstable to stay credible. It just doesn't stand out.