Last month I worked on map editor (maybe I should call it entity editor for a while, cause you can’t change geometry a lot).
So what can it do?
For now, it has:
- standard tools (select, move, rotate, scale, connect, clone).
- physics (you can create rigid bodies or collision objects, like boxes, spheres or cylinders, connect each with joints, add motors, change all physics parameters etc.).
- triggers (different types, timers to activate).
- events (you can add different events according to the object type: add impulse to the physics object, destroy connections, joints, change color, speed and whatever you want).
- particle emitters (you can add wind, gravity, size, color, random factory etc.).
- collision nodes (which you can connect to lines to create stairs, collision walls, corners).
- sound entity.
- simple gui (panels, buttons, lists, text boxes).
- save/load to binary “map” file.
So you able to create systems, which may interact with game world as a part of other systems.
Events and triggers (with timers) allows to create even more interesting systems. Here is a short video:
Now I can add things like: doors, traps, lifts, even simple triggered tasks for game player.
I tried to keep all things simple as I was able to do so (both code, and editor as a tool). I think now my game(s) development will get more acceleration.
By the way, I worked a lot on my game (”Respite”) conception too. Tried to clean up story line, refused some ideas as it doesn’t fit to the iphone game at all, also I was very busy with level design (you should see dozens of dozens sheet of papers around me 
).
Here is some concept art for game:
Characters
Vehicles and environment
Also implemented octree algorithm for game level space subdivision, in my opinion this should help to gain more performance on the iphone. As I working on iPhone simulator only, I can’t see actually performance, and this makes me nervous.
But I prepared lots of optimization already (PVR texture compression, reductions in the size of the all geometry vertex array (floats to shorts), interleaving vertex data, same geometry sharing for animated models – this should lead to significant performance).
One more thing: I am going to get iPhone (probably next week), many thanks to Woody Deck! 