Some of my favorate things about this episode:
Seeing Bulbasaur, Charizard and Squirtle together again. A sight not seen since Johto.
Bulbasaur standing on two legs.
Ash and Mays Squirtle's meeting each other.
Backwards cap for Ash, a rare sight in Advanced Generation.
Ash in his Kanto clothes in the Advanced Generation art style during the flashbacks.
Team Rockets metal ballon that by all logical standards shouldn't beable to take flight.
The fact that next episode Bulbasaur will most likely beat a Pokemon that Charizard lost to.