As a ball of tar, you can squeeze through small spaces, stick to surfaces in any direction including walls and ceilings, and carry small objects. But as you can expect from the makers of TripTych and Pontifex, real-world physics plays an important role. For example, you cannot stick to a ceiling forever as gravity will gradually pull you down. Puzzles in the game are physical, and require full use of your abilities. For example, you might need to swing from platform to platform, or throw a block across the room to flip switches that open the door. It takes a lot of practice to be able to manipulate objects, since the physics model is very realistic. So in order to grab and throw something in a direction you want, you need to run at it at the right velocity and release it at the right moment. It's hard to explain and harder to pull off, but once you get the hang of it, you'll be hooked for hours on end.
In addition to the great adventure, Gish includes two-player "VS" modes that showcases the physics even further. With a friend, you can play football and sumo wrestling. In each game, each player controls a tarball. The rules are simple to learn, but the unique tarball physics makes the games unique and addictive. I spent hours playing sumo wrestling alone :)
The full version of Gish costs a fairly standard $19.99 for a 43 meg download, while anyone wishing to get it on CD can purchase it for $25.95. With plenty of unique levels, original gameplay, and even cool VS mode games, I would gladly pay twice that price for this gem. A well-deserved finalist in the 2004 Independent Games Festival, Gish will delight and challenge even the most jaded adventure/action gamers everywhere. Highly recommended, and here's hoping that Chronic Logic will be around for years to come to bring us more unique physics-based games.