Play Online Papercraft Wars Game
This is one of the best 2 players games that you can find online. You can play against Bot as well in 1 player or bot mode. You have a tank that fires.
In Single Player mode: Press A key and hold to adjust power, and release to fire.
In 2 Player Mode: Player 1 can use the same control keys as Single Player Mode, and Player 2 will use the L key.
You can also play Tank Trouble which is also available with a multiplayer option.