I've got some information on the latest games electrotank will have to offer us.

Pixel Cannon
It is a real-time 2D multiplayer game capable of 2-8 players. Battle against other tanks (oponents/cpu)aiming to be the last man standing!

Controls
Use the arrow keys or w, a, s, d to navigate, the mouse to aim, and click to shoot.

To start a game
1) Login with any username. Click New Game.
2) Enter a game name. Password is optional.
3) When the game (room) is created, choose a level. It may take a few seconds to load.
4) Wait for players to join. You'll see them in the bottom right user list.
5) Choose Lock Players when you have all of the players that you want.
6) All players need to select the button I am Ready
7) Obliterate the enemy

To join a game
1) Login using any username.
2) Click on a game icon. Enter a password if needed. Join game.
3) When the I am Ready button appears enabled, click it.
4) Play


TankCore

I know less about this, however it appears to be very similiar to PixelCannon. One positive is that the graphics are 3D and very slick and classy.