This is a fairly interesting level for a number of reasons (although it could have been better, for reasons we'll come to shortly). It's the only time that Cosimo, the narrator of the secret levels, appears in the main track. It has a lot of unusual architecture in it, but it does it without violating the Renaissance environment. It has some neat mapmaking tricks, but is marred by some familiar mistakes (and some new ones).
TI so far hasn't really had a natural environment, and while there are plenty of human structures here, there are also tunnels and caves and other "untouched" areas. The map ranges from the huge canyon the player first appears in through a rather luxurious house to a huge underground church and the surrounding underground and aboveground environment. It uses a looping linear design that leads the player back through the initial canyon several times, although I don't see this as repetitive because the change is usually easy to spot. (although it would have been easier if the final door was completely closed initially, to prevent the passage behind it from appearing on the map view). The only thing I would complain about in this process is the way the last exit to the canyon prevents you from going directly to the door and forces you to jump back into the pit and run up the huge stairway again. There are other interesting bits of mapmaking, like the stone sculptures one encounters near the beginning of the level (complete with neat shadow effects), or the segmented platform rim one must open at one point, or the process of "breaking in" to the outdoor house by opening a small rear window and shooting the front door open.
There are two trouble spots in the level that taint the otherwise smooth progression. The first is a magic trigger polygon: to obtain the key to unlock the church, one must find a certain room and clamber over the furniture until the nearby window slides open, a rather nonsensical process. And, despite the Spoiler Guide's comments, the trick WAS done in exactly the way I thought it was :P (although someone who's not an experience mapmaker would have more trouble figuring it out). Secondly, at one point one encounters a library, which must be exited by following 343 Gui^H^H^H^H^H^H opening a secret door in one of the bookshelves. It's been said before, but it's worth saying again: The level's critical path should not be behind secrets, at least not without giving some sort of clue to their location. It's further muddled by the presence of a second identical bookcase, which produces a locked door sound when tabbed. Another annoyance in the level is a secret door which momentarily traps you in a dead end; it will open again after a short delay but that's more than long enough for one to assume he's run into a suicide trap and/or bug in the map and revert the game.
There's a lot of ammo that tends to float in the air for no apparent reason; bizarre but not a huge flaw in the level. Also in the "minor annoyance" category is the fact that the cross-shaped stained glass windows in the underground church are actually pulsating; this doesn't exactly ruin the level but it does ruin the illusion of a real Earth structure. And I never figured out what the "poop launchers" at the church entrance were meant to be.
As above, this level is the first and only time the mysterious Cosimo appears in a non-secret level. The philosophical point made in the level name and the spoiler guide is interesting but not very relevant as there's not much the player can do about it (as opposed to a game like Deus Ex, where it's possible to succeed in your objectives and enjoy the game while trying to minimize casualties), so the player is effectively ignoring the terminal's instructions as the level is played, unusual in a Marathon level. Then again, virtually all of TI's Earth terminals have been information only, as every single Earth level is an exploration mission.
