there should be dialogue, hp bars etc. to make sure that player will understand what they need to do. However, there were some problems, so I decided to remove them.
So there are 3 phases. Each phase lasts about 15-20 seconds. First, boss will try to chase you and you just need run, you can move diagonally to be faster. Second, he will still chase you but with dashes, there will be delay between each dash, so you will be able to move away from dash direction, his direction of phase will be place where you were at delay. In last phase he will move to center of map and release many bullets, and you need to move to edge of map and wait until there will some space between bullets, space will be small but collider of character is small enough to be able to pass between bullets.