This Achievement is Cumulative, meaning they add up over Playthroughs. So you DO NOT need to beat 4 bosses in one run. But simply beat the 1st Boss 4 times!😎
Tip for 1st Boss:
Try not to die in before the 1st boss. If so, you will have a Full Overload Meter. Press
to use the overload and defeat the 1st Boss EASY!