Tanki Online is described as 'free browser online 3D-action game developed by AlternativaPlatform company'. There are three games similar to Tanki Online for a variety of platforms, including Mac, Windows, Wine, BSD and iPad. The best alternative is World of Tanks, which is free. Other Tanki Online like games are Infinite Tanks (Paid) and BZFlag (Free, Open Source).
Infinite Tanks lets you do battle online and offline with a never-ending line of tanks and other armored combat vehicles. The game features a unique card-based construction system driven by single-player progression and multiplayer collaboration.
BZFlag is a 3D multi-player multiplatform tank battle game that allows users to play against each other in a network environment. There are five teams: red, green, blue, purple and rogue (rogue tanks are black).