To change sounds in a 2D shooter game created in Gamemaker:
1. Select the sound to change from the sound section of the Gamemaker menu. The first sound changed was "player_1_lzr_sound".
2. A window appears allowing changes to the sound settings. Select the small file button to choose a replacement sound file.
3. Navigate to the folder with the replacement sound file and select it. The code does not need changing as the sound name remains the same.