Are you all out of your minds? What is the point of having an invincible enemy in a video game. The purpose of a game is to WIN. You also haven't been following the STF storyline. The Special Task Force is a joint Klingon Federation fleet that reverse engineers Borg technology to create the best equipment in the galaxy. THat is why the Cubes can't adapt, because modern 25th century weapons are reverse engineered from Borg gear. And as someone with an Odyssey class battleship heavily modified with Borg shields, engines, deflectors and hull plating, it is impossible to defeat the Borg on Elite by yourself. Take it from someone whose **** head teammates have abandoned him to fight the Collective on his own. You need at least a battlegroup to truly beat them. Especially in the STF missions. Oh, and in First Contact the cube was destroyed with Photon and Quantum torpedoes. Mk 9 Photon and QUantum torpedoes. Weapons in STO go up to Mk 12.