To Start the Game: 1) Launch c4.exe 2) Display the command console using the tilde/accent key (just below ESC) 3) Enter grav at the command prompt. 4) Hit ESC twice. How to Play: You can control the gravity affecting objects in the space, or gravity acting on yourself. If you select an object, such as a crate, by shooting it, you can then use the numbers of the arrow indicator to make a given direction the "down" vector for gravity on that object. If no object is selected, then the same vector-display applies to you. You can open doors by making crates slide into them, by controlling gravity on the crate. Each passage must be opened by using a crate to solve the puzzle.