This level misfires in several ways, even though it's pretty short. The first mistake is visible in the map view: A boat's interior should not extend beyond its hull! I could accept a very tall boat, but I don't think any non-submersible boat has ever been significantly wider underwater than it is on deck. Secondly, the "surrounded by water" concept doesn't work very well. If I was designing such a level, I would make sure to set it at night, so the water could be darkened and allowed to fade to black, instead of just cutting off at some distance from the boat. It looks even better when using the Infinity space landscape, since the horizon would also be black and the edge of the water would be essentially invisible even under careful examination; the TI space landscape has glowing clouds on it so the effect wouldn't be as good even if this was done. There are other architectural oddities that ruin the illusion of a Renaissance-era boat, like the canals on the lowest level and the use of the marble floor texture. This level would be significantly more believable, with virtually no changes to its layout, had it been described as a small island instead of a boat.
As above, the level is quite small; one of the shortest non-secret levels in the game. Head up to the bridge to open the downstairs hatch, hit various switches, collect the ammo, drop into the lower bilges, hit the self-destruct buttons (another thing I doubt one would find on a real ship), and wait for the area to flood.
Don't forget to check out the message from the Pfhor in the book on one of the middle levels. This is the second time the Pfhor have spoken directly to the player in this scenario, after the vengeful Hunter on Polygonium Opus, and it's much less neat than before since it's not going through a computer. One can imagine a Pfhor struggling to trace out Earth letters under the direction of an Enforcer or distant command mecha. The battle between the S'pht and the Pfhor has moved beyond orbit, and they're going to start interfering with your mission more directly. Pretty soon, you'll have to take care of them once and for all...
