Decent concept, just a few flaws
For one, if you hold down the mouse and drag to the left during the early stage of the game, and just hold the mouse there for the entire game, you win automatically.
Secondly, don't make the cursor invisible until the beginning of the game, as it's hard to see on a white background.
Finally, it's hard to tell when the level's going to change directions, making it a bit counterintuitive to play. I'd suggest a flashing arrow, 3 flashes before the map changes directions, to give players a heads up that they need to be on the other side of the map or they'll lose.