I Have fixed some of the issues like the button(Somewhat), and ive made it so the boss starts moving once the boss room gate closes.
also the game has random map generation.
Yes, initially i didn't notice the map generation, but that's admirable. So i guess you can't really setup the level to avoid collisions.
Then probably a path finding algorithm would be the approach i'd use. It's a bit more advanced, but try checking out this video.
Also, good job on the sound effects, only maybe they are a bit too loud. You can easily adjust the volume, both from the editor and from code.
I guess the only thing missing is for the enemies to shoot at you. And about that, you can shoot through some obstacles, you they are thin enough ;)
Good work