A little while ago, the Experimental Gameplay Project theme was Zero Buttons: a game which could be played without pressing any buttons. I came up with something which was barely in the sprit of the thing, a sort of 2D maze escape game where you'd be pursued by hostile robots and a crumbling environment. I kind of liked the ideas I had for that, and have decided to return to it.
An escape vehicle exists at the far end of the complex. But the security systems are online and hunting for you.
After careful consideration our recommendation to you is...
RUN DON'T WALK
I've dug out the old tilemap code I wrote for that project, and converted it to use sprites for the tiles. I then wrote a cellular automaton (think Conway's Game of Life) to simulate the gray -- well, in this case, purple -- goo spreading across the map. It's a very simple rule where the more goo tiles are adjacent to a non-goo tile, the higher the chance of goo conquering that tile. This is modified by the current contents of the tile: empty space does not block the spread, whereas walls are much less likely to be conquered, and furniture somewhat less likely. The result is that the goo spreads and surrounds structures, but they remain intact for a brief period until a wall is breached, at which point goo floods the interior. I've also added Standard Video Game Explosive Barrels which, when conquered by goo, explode and clear out the nearby tiles. Of course, they are just filled with empty space and it doesn't take long for the goo to flood in again. All in all it looks totally sweet even with ten-second programmer art for the tiles.
Honestly, I'm having so much fun messing with this apocalyptic cellular automata that I don't know how soon I'll get around to the robots. I'm tempted to back off that part of the concept a bit in favor of a less hectic, more strategic thing focused around blocking the goo flood with various objects long enough to make your escape, but we'll see -- a lot will depend on how easy it is to get characters moving around the map. I'll also want to make it so that it takes a specific amount of time for goo to conquer a tile, instead of the event being random; this would let me design levels without worrying that the random number generator will decided to screw the player and flood the map too quickly for an escape.