Try to make sure u got some uber Meowcenaries left form first mission, but I managed with only 1. How I did it was got to bottom & take out aztecs, move up a little & start going diagonal up-right when boss comes & then down left after first fireball, then up-left after 2nd & down right & get rockkets at bottome & kill aztecs again. move middle of screen & wait for boss on right screen. fire rockets while moving down pick up more rockets, kill aztecs move to center. Boss come out on bottom, so fire rockets & move left or right then return to bottom when he's gone & get rockets & kill aztecs then move center, 4 more rockets should finish boss. Very hard fight, especially when aztecs get faster, but do-able. Much easier the more original squad u have.