errr 12 bats will kill 12 zerglings no matter what. Unless the person was like moving with firebats and wasn't attacking. 1 mutalisk does not own 2 marines with 2 medics. 10 mutalisk does not own 20 marines with 20 medics. M&M is usually supported with firebats. Firebats own zerglings. Lurker Lings are owned by tanks, supported with plenty of marines and firebats and medics. I say Zerg sucks early/mid game. They start to dominate around mid/late.