Clever game. My trigonometry is a little outdated, but the vibrating is most likely a function of line 101 where the velocity of the enemy is determined. The cosine of the angle that is being calculated doesn’t ever appear to reach that point to make that calculation = 0 and stop the velocity.
He may want to find a way to add a conditional to stop the velocity if the characters are touching (or something like that). At least that’s my best suggestion. Sometimes when you do the math in such a precise manner, you also have to add a condition to catch the cases that cause glitches like this.
Anyone else have a better idea?