Flui°D°emo - A 2D Fluid Simulation

Do you use some kind of accelerated structure to avoid O(n^2) physics/collission detection?

I know, a broad phase collision check with quadtrees or other techniques would speed up the collision test, but actually there was no need for this. The used SAT method is really fast and was sufficient.

The curent collision resolving is done in 2 steps:
1. The boxes (OBBs) are tested against each other and separated, if necessary.
2. The particles are tested against each box. If necessary an elastic collision is applied.

Looks damn cool. :o)

If you're looking for game ideas there was a game involving water simulation, guiding it from the top of a level to the bottomcalled Cataclysm.
Youtube video. Good fun game.

An alternative could be to add some more physics objects and create something like Armadillo Run.

Regarding the puzzle game, it should probably be mentioned that it implied 2 phases:
First: setup flow control with some given building blocks.
Second: water simulation.
The simulation only runs with ~250fps at 500 particles on an AMD X2 6400, and by separating the interactive part from the simulation part, you can actually precalculate the simulation and just play it back in 2. so it will run smoothly on pretty much any CPU.

That Cataclysm video looked interesting, the idea to place springs which require a certain pressure from the water before they move is pretty cool. But I wonder where's the challenge in that game? The little jetpack-dude can obviously not drown - he can actually "push" the water with his body - and can place "blocks" to change the intended drain's storage. Is the only difficulty not to release too much water at once? I imagine it's pretty hard to lose that game if you spend the "blocks" to increase the drain's storage room, so it cannot be overfilled.

[...]The simulation only runs with ~250fps at 500 particles on an AMD X2 6400[...]
So whats wrong with this framerate? Don't forget, a real fluid physics simulation is performed.
It's not just particle.Position.Y -= 0.01 or something like this.
And as I also stated in the first post, there are a lot of optimizations, which could be done.

If you want a look at the later levels of Cataclysm, I've found my copy and can make some videos if you want.
It was a commercial game that ran on RISC OS (which is a largely dead platform now) which can be emulated but involves grabbing semi-legal ROM images etc otherwise I'd offer you the game itself.

As to the lasers: it appears they're motion sensitive, they go off when you move in front of them, if you don't get out of the way quickly, you die.
There's also ways to "gain" more blocks since you have a limited amount (bottom left in the video).

If you want any more information on it, just ask.

Edit: An additional gameplay mechanic I found whilst playing is "mixing" the liquid.
For example on one level there's blue and yellow liquid. If you let blue in your time increases, if you let yellow in, your time increases, but if you let the liquids mix, you get green and that is what you have to guide to the spout.