In one player mode, the keys are as follows:

Either:																							                            			Or:
                    W                                                      5
                 Rotate                                              Rotate       
             Q           E																	                  			4                   6
    Move Left   Move Right							  					Move left      Move Right
            S            Z OR X                              2                  0
       Down          Drop														              Down            Drop

In Two Player mode, Player 1 (Left side) uses the keys on the left
			                                   Player 2 (Right side) uses the keys on the right

Also, in both modes, the following works:
                        ⌘Q   -    Quit					 							           ⌘P  -     Pause Game


When in the main menu, shift-clicking will toggle graphics modes.
When Quitting, holding down the Option key will stop the program saving your  
                            preferences, else they will be automatically be saved.