First of all, let me say that the problem is caused by microphone and game being recorded at two different frame rates. Microphone is recorded at true 60 frames per second while game is recorded at 59.94. So this .06 frame of difference causes the audio desync. So, what you do to fix that is, record microphone as a separate track and then in the video editing software of your choice (I use Hitfilm Express 2017, which is a free and very good video editing software) and stretch the GAME FOOTAGE until it matches the microphone track. Game footage will be shorter than the microphone audio by a few seconds (12 seconds of delay in a 1 hour video usually) so just stretch the game footage until it matches audio track. It won't cause any problems with the game footage like any sort of slow-mo as it is only a .06 frame difference but your video will no longer be out of sync.