To play "Tanki Online" for free as of May 2015, go to TankiOnline.com and click on the Play button. Create a nickname and password to register for an account, or register through a Facebook account. Select a Current Battle and click Play to join it.
Once you have a "Tanki Online" account, you can log in with that information. After logging in, you're taken to a home screen with multiple menu options. Click on Friends to view friend activity, incoming friend requests and sent friend requests. Click on Garage to customize your tank and purchase items. Click on Battles to view current battles, join one or create your own.
Control your tank using the keyboard. Movement is controlled by either the arrow keys or the "w," "a," "s" and "d" keys. Other tank functions controlled on the keyboard include firing the cannon, rotating the turret and self destructing. The full controls are available through the website's Help section.
"Tanki Online" is free to play; however, you can buy items with crystals. You can obtain crystals through achieving certain in-game milestones or by purchasing them for real-world currency. To purchase crystals, click on Buy from the home screen, select a payment method and the amount of crystals you want to buy, and then enter your payment information. Accepted payment methods include credit cards, prepaid cards and PayPal, as of 2015.