Sorry for a newbie's question, but how on earth can you turn around? I have keyboard and keypad only and with the keys I can move or jump only, not turn.
The game is mainly playable using the mouse to turn the camera. You can also use a gamepad (the left stick). Sorry for the inconvenience. If you have a special reason for not being able to play with mouse or gamepad, let me know and I may make you a special version with full keyboard mapping.