During my initial run at Oo-Topos, I had explored 77 rooms of this strange alien planet, solved very few of its mysteries, and left a few stones unturned. My final adventure of this run took me through a one-way vactrain leading to a confusing maze called the "fly room."
As it turns out, with the exception of that room and whatever else lay beyond the vactrain tube, I had already explored most of the map available to me without solving puzzles. The only further rooms uncovered by my post-hoc thoroughness were a pool of water near the garden and an oubliette below the catwalks where a rainbow-colored cloth sat.
The fly room itself is a six-room area floating above the top of a staircase. It isn't truly a maze, and can be visualized as the interior of a six-sided cube where unusual gravity permits walking on any side, and the compass points become relative directions. Within each side is a portal that you can enter by going "down," leading to yet more areas.
The west side of the fly room opens into a small security room with a pressure suit and a viewscreen, through which we can see a cold storage room where the serum is kept.
The top side, on which a seamless box is found, opens to a pyramid, which can't be entered but a PSI cube rests at the top. Inside, mosaic patterns show a ramp extending from the prison roof to the jungle below, and a bar of silver can be found. Taking it causes an alien mummy to pop up, curse you, and take your valuables (which at this point consisted only of the silver bar).
The north side opens to a bending tunnel that exits to the jungle, another maze. With 16 rooms, most of them having seven or eight exits, this is the biggest one yet, and made tricky because while not all of the rooms have the same name, several of them do, with three rooms called "jungle," four called "dense jungle," and three with a variation of "jungle path." Without using items as breadcrumbs, you might travel north from "dense jungle," arrive in "dense jungle," and have no way of knowing if that was a different dense jungle than the one you left or not. Gathering enough breadcrumbs is another problem in itself - you can only carry six items at a time, and finding your way back to the tunnel so you can collect more isn't trivial, as the non-othographic layout means you can't simply reverse your steps if you're lost in the middle of the jungle. And then there's the problem of getting back to the other side of the one-way vactrain.
Finishing the jungle map was my greatest challenge yet, and yet once mapped, it's pretty elegantly laid out. While there's nothing at the end of the maze except for some thorned bushes, within the maze I found a double helix healer at the top of a tree, a navigation chip, some Terran relics, some seeds, and an emerald flower. A pit south of the start held a 6502 processor and a path to a gravtube dumping me back into the fly room, and a path north of the start was left unexplored.
The bottom side of the fly room opens to a dead-end with the words "Tugo-tusta" on the wall. Typing these words teleports you to the solarium and back, which was how I got more items to use as breadcrumbs.
The east side leads to another pit. At the bottom is a fearsome beast called a "tras," and a needler weapon by its feet. I tried shooting it, but it dodged, and the tras attacked, which I automatically dodged. I walked away into a room full of bookcases but only one book - a repair manual for intergalactic class ships, written in English. The tras followed and blocked my only way out, so lacking any other evident options, I shot it again, this time killing it. Another room accessible here is a steel door to a room that's too cold to enter, which must be where the serum is kept.
I returned to the unexplored path, which bent around the prison, and led east to another maze, one made of shifting vegetation, beach, and sea, where I found the stripped hull of my ship lying in the center. This maze was smaller than the jungle, but no less confusing, and to make matters worse, entering spawned a "crabbette" which followed me around everywhere, even leaving the beach, and each turn would have a small chance of killing me with a venomous bite. Shooting it with the needler did no good either.
After mapping it out with ample use of item breadcrumbs, I was pretty satisfied that I had charted most of the game. At 135 rooms and counting, Oo-Topos may be the biggest microcomputer text adventure game I've played yet, edging out Cranston Manor Adventure's 132 and Colossal Cave Adventure's 127. Only MDL Zork and its 161 rooms dwarfs it, and Oo-Topos may prove to be bigger still.
My next challenge is to solve Oo-Topos' puzzles proper. To repair the ship, overcome the obstacles, and maybe even fix that bug that makes it impossible to get the serum.
My map so far - note that to keep the mazes readable, I have eliminated many of the redundant passages: