The Ravenwatch trailer looks really cool, keep spreading that thing around. I know I've shown it to some friends as an example of what to do.
The theme I'm going for should be reminiscent of a temple. The color was based on some pictures of types of sandstone, but I scaled it down a bit since the original looked a bit too pink.
http://cdn.zmescience.com/wp-content/uploads/2012/06/limestone-wave.jpghttp://images.nationalgeographic.com/wpf/media-live/photos/000/011/cache/sandstone-swirls_1180_990x742.jpgThe waterfall is animated, but needs some more work. I'm also going to make flowing channels so the waterfall can turn into a maze of rivers.
Edit: Heres the prototype animated version.
The main push as far as story/gameplay is to send the heroes into the Temple of Turak, a place of power which wizards constructed in order to harness the magic of Turak. Unfortunately the main antagonist (the titular Archnecromantrix) has also figured out how to harness this power so the heroes must destroy the Temple and free Turak in order to chip away at her power.
Most of the challenge is going to be big setpiece rooms, very open but cut off by a maze of flowing waterfalls which need to be deactivated in order to progress further. The theme will also need a lot of ancient-looking stuff to reinforce the look like some ancient creature was bound under this building.
Random Gameplay Ideas
-Some doodads will have "help text" which is scripted to pop up when players are nearby, just to throw in little tidbits of backstory as they progress.
-The main type of enemy will all have the summon ability (but only a single use, or cooldown set to an arbitrarily large number), which they can use to summon in 3 of the tier below them. Slowly ramp up the tension until players dread finding a whole room's worth of encounter inside a single foe.
-Going to let the theif unlock an ability called "Steal" or somesuch, which will let them take certain doodads and turn them into money. Script-wise it will just work the same was as destructible walls with the "on hit" kind of behavior, but instead of opening passages it will just produce gold. Essentially letting them "steal art from off the walls" Just another way to hide secrets and force people to constantly keep an eye out for all the deco-doodads I took forevor to draw.