Trinity surprised me by being a fantasy game about nuclear weapons. I expected the game to have a sci-if feel like Jigsaw or Babel, but this game was very similar to the feel of Moriarty's other Infocom game, Wishbringer. In both games, you travel from an opening, normal world to a parallel world, where helpful animals, witches, cemeteries and grim birds await.
I loved exploring the main area of Trinity, and accessing several of the mini-areas. Brian is stunningly creative; I didn't realize until recently that he also wrote Loom, one of my favorite graphical games of all time. The sheer ingenuity of it all is wonderful.
I began running out of steam forward after visiting four of the sub areas. I went to a walkthrough, and discovered that I had forgotten to revisit some area with new equipment, and hadn't searched some scenery items that I didn't know we're searchable. This opened up two more mini areas, which I explored a little bit more before using a walkthrough the rest of the game.
The final area was a beast, although everything is fairly well hinted at. Or not... In any case, I loved this game. I can't help but enjoy this author's worldview.