Phase one:
Goober starts mostly defensive, having a blocking position with him fists, and every once a while swings a punch. If your hit, it does 5 damage. You do not attack Goober, or else it triggers and animation where he tackles you off the building, eliminating you both.
When he pulls out his pistol, you can attack now, but you want to dodge his shots, because they will do roughly 40 damage each and it will cause a stun. When you become stunned it will go slow motion and Goober rushes towards you to do a punch, this triggers a quick time event where you must press certain buttons quick to dodge the attacks, and perform a counter attack.