Scratch

http://scratch.mit.edu/projects/RedRocker227/2155512

Keep going right until you get to the door bit. Then try to go through the door. You'll notice that the majority of the time, it will work, and you won't go through. However, it looks really messy when you hold the down key when above the door, and occasionally, if you switch from pressing the down arrow to the up arrow almost instantly, you can get through without the key.    I tried using a variable to store the sprite's direction, using colour sensors, and checking which key's held down, but they all produce that 'messy' effect.

Any help is appreciated!