Today some idiot tried to use Ojama King against me in the first turn. In the second turn I used Soul Exchange and used his Ojama King as a Tribute to Summon my Gravekeeper's Chief. He surrendered. This is a very weak strategy.
Hardly anyone runs Soul Exchange or Tribute to the Doomed these days.
Monster removal is performed via monster effects nowadays.
So, if you do manage to summon Ojama King on the first turn, you will win 99,9% of the time.