Thanks for the comment.
When you press left mouse click, then drag it and release, you push your character in the direction: from point, where mouse was released -> to position of your character. Direction is also shown by the arrow near your character. The further you release your mouse from the character, more velocity it will get, which is shown by arrow color. (green min velocity- red max velocity)
Though the thing I didn't intentionally hid the mouse pointer, you are supposed to play with it, otherwise it will be quite hard to get the right direction.
Could you please tell which browser do you use?