I feel like once I got the gun cannon, they only thing that slowed me down were the shield enemies. Other then that I can just spam spread shots to kill enemies before they even get close. It just felt overall far less strategic to me and lost the sense of strategy and challenge. I would suggest removing it from the game and replacing it with a different upgrade, such as maybe armor piercing bullets for the shield enemies? This would keep the game interesting and balanced at the same time.
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