Recently I've come across to fortunate resources, someone offering to help with audio later on, and an excellent audio source in the mean time. Freesound.org, great place :)
Here's a break down of whats done or started so far.
Water - Works nearly 100%, although exiting is too quick/sensitive right now, but I solved the jump out of map problem I'm pretty sure. This includes on top of water, underwater, on water or in water that can't be used as an exit. Splashes and sound effects, plus sound changes underwater.
Sound System - The basic sound system, currently 3d isn't supported, but is simulated with distance checks on a three point axis. Includes such things as ambient fire, drip splashes, water swimming, thuds, foot steps. Sounds have at least more than one variation except for pickups and special ones. For example the foot steps is 4 separate sounds.
Instances - Basic throw-away objects like drips, splashes, bubbles and smoke. More to come like Jib and Scrap types.
Emitters - Spawns things like drips, smoke, bubbles and the likes.
Pickups - Base code provided by Ken, so I'm just adding to this.
Dynamic Light - Fire flickers, the player produces an ambient light that changes when underwater.
There are some other things I'm not mentioning, because they were provided by base code from Ken, handling various basic stuff that the build engine could do. Doors, rotating sectors and such.
Currently the next pending task are jib and scrap instances, inventory system and some basic monster tests.
I'll be releasing demos with a simple test map in the future, so I don't have to use the main one for testing stuff out and potentially messing it up. I've actually restarted the first map, so the demo version map is deprecated. However new screenshots will reflect new level design progress.