=SUM(IF(C3="Pistol"; +2;
     IF(C3="SMG"; +1;
     IF(C3="Shotgun"; +2;
     IF(C3="Assault rifle"; +2;
     IF(C3="Sniper rifle"; +3;
     IF(C3="Rocket launcher"; +4;
     IF(C3="Laser"; +4;))))))) + IF(D3="Tediore"; -1;
                                 IF(D3="Torgue"; +2;
                                 IF(D3="Chrono"; -2))))