Before you begin to read this review I'd like you to drop any pre-conceived notions you have about this world. The media is usually never kind to this game.
This game is suited for the 18+ audience. If you are not of this age please visit http://secondlife.com/. You may still refer to this review as I believe both versions are exactly the same but the teen version restricts content.
Another notice. If you are of age to play this but do not wish to see mature content you can filter it out with the appropriate buttons when you are searching places, people, groups, etc. Treat this like google when you search places. If mature content is enabled then you might get more than just what you wanted when you search "Club".
First, let's talk about the Game-play. This is a very hard topic to explain as what you do in SL depends entirely on you. If you want to shoot zombies, you can. If you want to go to a club and dance your heart out, you can. Explore haunted houses, watch a movie, ride a rollercoaster, you can! The game is basically one giant sand-box. Meaning, everything in the game is made, coded, and ran by players (except the game itself of course).
Keep in mind that this game is aimless. There is no set goal for you to achieve here but much fun to be had. To go along with this the world isn't connected. Instead of being on one giant land mass you're divided into regions called "Sims". Each Sim is different and its contents are based on who owns Second Life Linden..
Confused? Well, let me try to explain it. There's a button called "Build" that lets you start creating (you can't build in most places as to avoid a spam of objects, press ctrl+F, click the places tab, and type in sand-box. Find one you like and teleport there. These are the designated building sites).
So, when this build menu comes up you can choose shapes and if you click the ground it creates itself there. Now, if you right-click whatever shape you made you can edit it in many different ways. But if you click the content tab you will notice you can put or make scripts in there to make it to a wide array of things. You're probably thinking, "Hey, if all I have are these shapes then everything in this game must be all blocky!" Don't fret, I'll discuss that when we get to the graphics section. Also, since you can build anything you can also look like anything. The customization on here is endless, you can even be Sonic the Hedgehog!
To continue, you can build anything your little heart desires and then script it to make that creation do what you program it to. But you don't have to choose that path. You are more than welcome to enjoy other people's creations and worlds. As I mentioned earlier, you can press Ctrl+F to search places you want to go. Some examples would be Amusement parks, Clubs, Combat, Racing, etc. There are many things to play and explore, you just have to find them.
The graphics in this game differ depending on who made what. This is difficult to explain in words, so here's some examples. A perfect example of how these shapes can turn into wonderful creations is by looking at the screenshot with the cat in it. Also, this game can be a computer hog and you may lag depending on where you go.
Some places may look like this.