Kazap.io

This game is fast-action, and uses tank controls. It plays like an FPS, not as much like an IO game. It uses WASD and arrows for rotation, thrust, and reverse, K or X to shoot, Z or L to brake (stop quickly and rotate slowly), and spacebar to use the boost ability.
Everyone is very lethal, so even small players can threaten large ones, however collecting and growing can happen very fast, especially if you take down a larger player, which is challenging, but possible and extremely fun to do.