We're a nautilus floating in an 9x9x9 three-dimensional world, with each axis representing a different environmental quality: temperature, pressure and turbulence. Puzzles revolve around using these environmental scales to affect objects; although, as we solve puzzles, we gain powers that could open up alternative solutions to the remaining puzzles, or at least make life easier. Eventually, we create a new world for ourselves; up to now, apparently, we had simply been wandering from one established world to the next, so this world-creation business is something special.
I appreciate the use of scientific principles in the solution of the puzzles. It makes the game, in spite of the magic-based setting, comfortingly logical. But I think the thing I appreciate the most is the occasional reference to previous worlds. This gives the whole game a depth it would not otherwise have: our protagonist may be a nautilus floating in space, but it's a nautilus floating in space with memories and a history. It's like how Zork III, otherwise a big puzzlefest, broke me up in the first room by referring to the brass lantern as "your old friend".
"Ether" isn't the only game this comp to do this, but I think it's the one for which the trick matters the most: other games can depend on voice and setting to catch the player's attention: "Ether", with its cold logic and intellectual approach (refreshing, in a way) doesn't have quite as much of that luxury.
A plain cheese omelette with cubes of melon and mango on the side, hot Chinese tea and cold orange juice.