YOU'RE PLAYING: Beast Hunter Game.
'S' is up, 'X' is down, 'C is right and 'Z is left. Or you can use the arrow keys.
Use the mouse to aim a shoot. Hold down for rapid fire.
You can upgrade your hitpoints and arrow damage at the end of each mission with the gold you collect and are rewarded with. Aim of the game is to hunt down and kill as many monsters moving eastward (to the right) until the end of the map.