I was talking to some guy. He said that my movement concept in game is bad. When left or right arrow is pressed I'm scrolling background what makes you feel that player is moving (player's X remains same). So... he told me something about matrix view. I should create all walls and platforms static and scroll only the camera and move player's rectangle. I did a little research in Google, but nothing found. Can you tell me anything about it? How to start? Maybe links, books and resources? My programming language is Java (2d). Thank you!