A platformer set in a sewer. Use WASD or arrow keys to move and space to jump. X to attack. Down arrow or S to crouch. Step on a gravity tile to activate it and flip yourself upside-down

 In case anyone cares here is the lore:

 The kingdom of Elaria was peaceful and everyone lived in harmony. But then a green glow came from the sewers and monsters poured out. Your father died protecting the kingdom. Now, you take up his sword and armor and go to the source of the scourge plaguing the kingdom