DroneOut

After clicking start, you're placed in an arena with an AI player. Game consists of waves and to start one press the 'F' key. 

You can attack enemy drones by firing your gun using left mouse button which deals more damage, or use melee attack with your 'V' key. On the display on your gun, you can see (from top to buttom) amount of ammo in your magazine, amount of ammo you have stored and health bar. 
To replenish your health or ammo, pick up rotating bags enemy drones sometimes drop when killed.

When you get killed (your healthbar reaches 0), you will be presented with a statistics screen and a leaderboard dialog where you can input your username and get to the top of the leaderboard! You can check out the leaderboard here: http://nufflee.com/droneout .

Controls
Mouse movement - look around
Left mouse button - shoot with your gun
'R' key - reload
'V' key - melee attack
'F' key - spawn next wave (if current is finished)