I finished season 2 the other day. George Reeves is just excellent as both Clark Kent and Superman. Noel Neil takes over as Lois Lane for Phyllis Coates. There are 3 episodes from this season that were my favorites.
The Defeat Of Superman introduces Kryptonite for the first time on the show.
Superman In Exile features Superman stopping an atomic disaster. He becomes radio active and has to retreat away from civilization.
Panic In The Sky features Superman attempting to stop an asteroid coming to Earth. He fails to completely stop the asteroid, and he gets amnesia from the impact.