I'm happy to report that I finally made it and killed the boss :) it was achieved with level 3 lasers on the front, level 2 (or 1) on the back, and a special weapon missile launcher up top. Maybe one additional point of feedback: I think the weapon choice would have been more user-friendly if it was possible to select a weapon with the keyboard and not by mouseclick. I lost a life a couple of times by having to select a weapon when an enemy was nearby, because my right hand was on the mouse and my left on the WASD keys, I was unable to press the spacebar when necessary. Very minor thing though, overall an excellent experience!