The story itself matters little when it comes to playing the game, but does add an interesting element for the more dedicated. Occasionally, there will be a cutscene with another part of the story played. For example, one level's obstacles are explained by a sign to be a filtering system to let in only the best goo. It's split into five different chapters and influences the design or layout of levels you play through. It's easy to miss, especially if you ignore the signs littered throughout levels. It's also not a very quick process, which can hinder you on levels or in situations where moving quickly would be better. Goo is continuously moving around the structures you build, overlapping each other and previously placed goo. While it is quite easy to do, sometimes actually getting the goo you want can be a challenge. Simply click and hold the ball of goo you want, then release it in the right spot to build. Gameplay in World of Goo is rather simple and straightforward. There are also many points during the game in which you'll have the choice between two different levels, so if you're having trouble or stuck on one you can move to the other. If all else fails, you may also have the option to skip the level completely (but the number of skips is limited). There are “Time Bugs” that can be clicked to undo moves if you mess up (which can happen quite often thanks to the wobbly nature of the goo). Signs located on every level will often contain some sort of hint or tip to help guide you.

Fortunately, even less experienced puzzle players will have some help. World of Goo is quite easy to pickup and play, but very difficult to master. These give a great reason to replay the game and levels several times over. Use the goo to build a tower as tall as possible and compare to others across the world. Goo collected during levels can be used in free-building in the World of Goo Corporation mode. Additionally, you can replay levels over and over to try and better the number of goo you collect, the number of moves you took, or the time the level took to complete. The wide variety of levels and goo type means that even though you're doing basically the same thing for every level (building toward a pipe), it will feel new and different every time. There are a surprising large number of goo types slowly introduced whose unique properties are required to complete the levels. Some goo can only be placed once, while other goo can be placed and replaced. There is goo that will act as balloons and lift your structures, or matches and spread fire. The goo balls you need to collect come in various colors and looks with their own unique properties.

The levels aren't the only thing that is diverse.

World of goo free game