have anyone have this bug: First, the boss appear and already enrage. Boss' armor is at low. After it was destroyed, the game won't end. Also the boss' ship is smaller than usual.
Tips for defeat boss level 18: Just equip abilities that mostly for damaging like "Psion Wave." Also Healing Technique, Guardian of Mana, Stop Time, and Darkness Energy Charge. Also equip missiles. It works for me, see if also works for you.
Did everyone notices, when an enemy ship use "Rapid Shield Recharger" then you go near it appear a circular light surrounding the ship. If you in range of that circular light your shield were also recharged!