Recently I’ve been in a Tetris mood.

You know, sometimes you just want to fit blocks together. Sometimes, you just want to watch the world simply fall into place.

Back in the day, I would play in www.tetrisfriends.com. I wasn’t especially good, but I was good enough to put up a more-or-less decent fight against my friends. So, when I decided to start again, I had at least a few tricks up my sleeves.

But this time, I started with Facebook’s Tetris Battle.

Now, with Tetris Friends, there was a special game mode — Battle 2P. In this mode one player had to clear lines and send them across to the other player.

Playing against my Honorable Opponent Jazzy551.

Tetris Battles on Facebook also had the same mode, but this version looked a lot different.

HELIN PIEDRA…, my worthy adversary.

Now, both games were developed by the same publisher, Tetris Online, Inc, so it’s really not surprising that they seem very similar. However, the differences are much telling than the similarities.

Tetris Friends is essentially what a Tetris fiend expects when playing Tetris — five preview slots, a hold slot, and nothing else. No frills and no additional things to worry about.

But look at the Tetris Battle.

I’ve boxed the differences for you!

First off, let’s look at the bottom of Tetris Battle. Most prominently, there is the friend bar, asking poor, lonely, Edward Martrain to invite his friends. All of a sudden, Tetris has become a social thing — like Farmville. You can see all your friends and see how good they’ve become at Tetris, and even send them little gifts. Such a thing simply does not exist for Tetris Friends.

Next, you see the Shop and the My Stuff buttons. These people, Tetris Online, Inc, have managed to monetize free Tetris. To monetize it. They’ve introduced special items that give you an unfair advantage (the stack of three squares on the left) and have locked the preview boxes (Stack of four boxes on the right). And then, they give you the option to buy these items and unlock these preview boxes.

On the top you can see exactly how to buy things in the e-shop — with the coins and cash you earn as you play. Now, you can gain them in a couple of ways. The first, is the “Buy Cash and Coins” tab. Pretty self-extraordinarily, you buy in game currency for real world money. Next is the Earn Tetris Cash tab. Essentially, you sign up for various services and gain Cash for doing so.

Wow! Cash for FREE!

The last way to earn is to invite friends and have them sign up and possibly buy some cash.

The last difference is the blue energy bar at the top. Every game you play spend five energy. When you run out, you’ll have to wait for your energy to recharge before you can play again. Or alternatively, you could buy more energy.

When Tetris was Facebook-ized, it was also Farmville-ized. It was gimped and monetized and a million other things’d. If Tetris Friends was the valedictorian of online Tetris, then Tetris Battle is it’s cripple of a brother. Tetris Online, Inc clearly thinks that Facebook users would be satisfied to play a Farmville version of Tetris. Tetris Online, Inc believes that people would be happy to pay for what they get for free, in the return for the ability to see friends online.

And it seems like they are right. With 11 million users, Tetris Battle is in no way small.

The question is, why does this succeed? Every single game on Facebook is the same too — following Zynga’s pay for online cash strategy.

The question we should ask ourselves is why this happens. Why would Tetris Friends and Tetris Battle be so different? What is so different about the Facebook population that makes Tetris Online, Inc know they can monetize it so much more?