Up arrow to jump, double click the up arrow to double jump, right arrow to go right, left arrow to go left, c to shoot fire at ghosts. The fire shooting command is a little glitchy. All you have to do is reach the red flower, if you touch a spike, ghost, or if you fall into the water, you go back to the beginning of the level.
This is sort of my first real game and it only has 3 levels so far.