Step 1: Movement

A programmer must have total control over every element in their game, especially movement. The default platform movement is sloppy and full of bugs. Our first step, is to build a basic custom movement engine.
The events above move the player left and right while holding the arrow keys. The negated opposite direction is required to hold the player in the current direction if the user presses both keys at once.
Now, we must resume the Stopped animation if the player stops moving, or presses both keys at once. Note that pressing both arrow keys with the default platform movement will make the player move left. This will never happen in any real game!
Lastly, we must center scrolling on our player, and while we're at it, why not hide the mouse cursor.
3