arrows to move wasd to dash (if you have all four crystals) touch a pool of water, your bed or a stream to heal. once you have all for crystals you can kill monsters by running into them, else they hurt you. you will loose health naturally due to hunger unless you have superpowers. get all four crystals to open up a portal to the void where you fight the final boss, kill him by getting blue orbs and firing them at him (They fire on their own.) The portal may be a bit difficult to find.
Let me know what I can do to improve the game, it has a lot of bugs.