Supraland

I cheesed it a slightly different way, though no less successful. Pretty fast.

I ran in and turned off all the shield generators and then went to the far end (opposite side, away from the vendor) and positioned myself a good distance from the boss with a large pipe directly between us. The boss tried to get to me straight through the pipe, never making progress.

I then killed all the minions around me. After that, minions spawned but they were too far away from me to notice me and come bother me. From there, it was easy: I just used my gun to shoot just to the right of the pipe the boss was behind and used the secondary gun beam to explode the gun shot just on the other side of the pipe. It did not take very long for the boss to whittle down and die.

Good luck to everybody.

There is a cheese method for this. If you have the magnetic belt buckle upgrade you can ride along the center pipe and position yourself inside and just keep dropping your purple cube on the boss' head. Takes a few minutes, but it's easy to do without needing all the upgrades and can be done without taking any damage. One thing to mention is to just be aware of the minions... Somehow they try to get themselves inside, but if you continue to just spawn purple cubes on their heads, you will eventually kill them all as well as the boss. May be worth adding to your solution.