Use the WASD keys to navigate towards the treasure chest. You can use blocks to build a path by pushing them into the water. Be cautious of slimes, they will move towards you when you are in front of them, avoid contact at all cost. In later levels, move into fireballs to pick them up, then click on a slime to fire at it. Keep in mind that you can only fire in straight lines, either vertically or horizontally, but not diagonally."