I always stuck at arachnotron because the missiles is so fast and there is no room to evade it. For the laser attack I know the attack pattern,its just the missiles so annoying
Stage 5 has an EMP. I think the devs thought it would be difficult to not only dodge the bullets from a Boss but also avoid being EMP'd too. If you get EMP'd during a boss fight, you're left with no method of attack at all so the boss in this case is just avoiding being Electro Magnet Pulsed. It disabled main cannon, wing cannons, missiles, laser, energy shield and mega bomb all at once leaving only your magnet for gathering stars...and that's it.