Wait, is this a flashback? I am sure Satou already used his Meteor Showers to wipe out all the Lizardmen (and other species)! Why are they shown again when they are already all dead?
Cross-series jokes aside, I can understand why people might be upset about this episode, but unfortunately it's part of the medium. Light Novel readers got the entire arc in 1 package, but here people have to go chapter by chapter and it takes about 4 weeks to see an entire novel volume be adapted.
But don't worry, folks! Next week we will probably get to see the absolutely best scene of volume 4 of the Overlord Light Novel!
A hint:
"
Shallchair"