Forgot what a game was called?

I once played a really funny game I would like to play again. The problem is I don't remember the name of the game. All I remember is that it was really funny, I played it on my computer, and It was all black and white and kind of looked like a drawing with simple lines. The little character would move around with the arrows on my computer and would slide if I pressed more for the character to move faster. I also remembe the game made you think a lot, and at one point the character dropped a key into a grate in the floor. Please help me figure this out. 10 Points to whoever can tell me what this game is called, and if possible where I can play it. Thank You!