So there are these giggling little globs of goo that you can drag about with the mouse. If you place one near some others, it'll form a wobbly structure by connecting itself to them with squishy struts.
And about half an hour into playing World of Goo, the obvious point of comparison finally hits me: it's Schindler's List. This is the game of Schindler's List.
You're trying to build towards this pipe, you see. Once your structure is high enough to reach the pipe, any goos you haven't used yet wiggle eagerly up to it and are sucked to safety. But the ones you used to build your structure are left behind, fixed in place forever.
"I could have saved so many more!" I suddenly wail. "I could have got more out! This flying buttress, why did I make this flying buttress? That's ten goos, right there! This support strut, that's another two goos! I didn't do enough!"
Cruelly, the game even plays on your guilt. The goos you save from the lolocaust accumulate at the Corporation Headquarters - an open level where you can use them to build into the air indefinitely.
Your current tower height is uploaded to a central server, and you'll see clouds representing the height of your friends' towers. It really rubs it in. Oskar Schindler never had a cloud tell him how many more Jews all his friends saved, and how high a tower you could build out of them.
But World of Goo's levels proper are much more interesting. The game has evolved from its early prototype, in which you simply had to build as high as you can. Now levels ask you to build over huge chasms and around fatal spikes, to wedge your structures in chimneys, float them with balloons, and even build on water and in a tumble-dryer.
Before long, you're actually building your way out of a creature's stomach. First you've got to make a raft on the sea of his digestive juices, obviously.
Then you build a tower on that to reach his oesophagus, whereupon churning muscles rip the top of your tower right off and physically vomit it out of the thing's mouth. So you build upon its lips. And from there? Well, there's no pipe to build towards. But the answer is surprising and beautiful, so I won't spoil it.
That's all in the first and most basic of the five chapters. There are more weird types of goo we haven't seen yet, and all the levels built around them.
Goo has all the gnarled cuteness of Psychonauts, the wonky genius of Armadillo Run and the infectious warmth of Darwinia. Actually, let me put that in terms that don't require you to have played a load of games very few people have played: it's cute, ingenious and heart-warming.
You and I have already helped save a few indie studios with some canny buys, but we haven't saved nearly enough.
Creators Kyle Gabler and Ron Carmel left Electronic Arts and risked their livelihoods to make something wonderful like this. Let's add them to our list - World of Goo is only ten quid, and you can already pre-order it.