World of Goo is a physics-based game in which one builds structures using balls of goo. Your missions generally revolve around escorting these balls to a tube, which vacuums them to safety. After each completed level, you are given stats on how many moves it took you to reach the end, how many goo balls you saved, and the time you took to do so. The first game that I thought of when I first started playing was the classic Lemmings, where one had to assist the lemmings onscreen to a particular destination. World of Goo, however, does not have as harsh a learning curve but is no less innovative in its concept. Personally, I do not buy or play many puzzle games, but I am impressed with World of Goo. Considering that the game was designed by literally two people, it is much more polished than expected. The graphics are simplistic but vibrant, and the music and sound part of the game is engaging as well. I was also pleased by the physics aspect. The structures you build sway and move in accordance to such factors as wind direction, the size of the base of your creation, the amount of remaining goo balls, etc.
The mechanics are easy to get a grasp of. There are five chapters, which consist of multiple puzzles. Although there is no manual to guide the player, the levels are accompanied by wooden signs that have written clues in case you get confused. Most of the time, I did not need to consult them, but they are entertaining to read regardless.
Despite the basic concept of building structures, the game manages to be creative in some ways. I have encountered several different stages that break the monotony of simply building the highest tower. In one stage, you have to build a structure to the tube at the top of the screen. The one caveat is that you have to build it within a "tumbler, " which rotates and shifts your goo balls' environment; this forces you to build something that can withstand the constant movement of your surroundings. It is fun and challenging at the same time.
The game is only single player, although you can submit your scores to an online leaderboard. Since there is no incentive to play the levels again after beating a puzzle, there is little replay value. Technically, you could go back and try solving them again with as few moves and in as little time as possible, but that would not be sufficient for multiple playthroughs.
The size of the game is fairly small at 67MB. It does not need high system requirements to run, and it is available for Windows, Macintosh and Linux OS.
Considering that I mostly play FPS (first person shooter) games, I currently enjoy playing World of Goo. I paid $0.01 during the game's birthday promotion on their website a couple weeks ago, where users could download a copy of the game for whatever price they wanted. They no longer offer this deal, but you can still obtain the game for a low price. I have seen prices range from $5.00-$20.00 generally, and it is definitely worth it. While there is no reason to play the game again after one or two completions, it does provide a fun and intellectually stimulating experience.