I was thinking about ideas if I were to design a boss, and I came up with an idea for Plank. As he can manipulate gravity(fly), he could fight a bit like Mothula from A Link to the Past, throwing spikes across the screen from one side to the other.
Also, about blaster upgrades... according to the trailer, there will be a teleport beam. Will you disable this like Metroid, or will you change it with another system, like switching each time you start charging?