Duck eats rock, duck earns coins, duck buy upgrades!

In this game, you play as a duck, whose objective is to eat rocks to earn money and buy upgrades.

Tutorial:

WASD to move (of course), do you see that rock over there? Go and press "E", you will get a rock. Hold "Space Bar" to start chewing it. When chewing, the duck will start to lose energy, to revocer it,  just stop chewing. Once the duck finishes, you will receive a coin. Use coins to buy upgrades such as: Energy recuperation, less chew time required to eat rocks, more energy, increase coin gain and more space for rock