Combination between method 1&2 Choice of either mode

In one-player mode, the user can use both buttons, and in two player mode only 1 button is used for each player. 

Positives Negatives
Option of 1 player or 2 player game, ie you get the advantages of both modes. A bit more complex to code because it requires more logic.
  An additional step in the game startup is required of the user

Method was chosen