The game that comes to mind is Portal, which took a very simple concept and developed it into an imaginative, funny, polished three-hour gem. World of Goo worked out at more than twice the length, while being no less polished, or funny, or imaginative. Those are big names and may render your expectations unrealistically high, so here's the negative. World of Goo's list of flaws: sometimes, when there are a lot of goos, it can be hard to quickly pick the one you want. That's it.