Not too good
The graphics were done so cheaply and purposely made so simple, that combined with the bad collision detection made the game a pain. This game is a lot like this comic from xkcd <http://xkcd.com/169/>. Acting smugly when "misunderstood" (calling it the world's hardest game, when really it's the worlds most unfair cheap game) isn't a good thing. To make it better, you could possibly make the graphics better (use gradients, add motion blur, make the coins shiny, more creative backgrounds and coloring, etc.). There could also be things like enemies that move towards use, give the player a weapon, etc, etc.