Dio with a gun!!
I'm so glad you mentioned Flash games because that was definitely what I was trying to channel. You're on the right track with the patterns: he can shoot in a circular pattern, a cross pattern, and a random pattern. All those patterns start at different offsets to give more variety. I agree with your feedback, I think either telegraphing his patterns or giving the player more time to react would be good improvements. Thanks for the kind words!