I absolutely loved this episode- it's one of the best in the entire series.
Obviously the main highlight was Charizard's appearance. Yeah, Charmeleon's evolution took place too fast, but it was definitely worth it to see Charizard fight Aerodactyl and establish itself as Ash's powerhouse.
I enjoyed everything else too:
- Gary appears and digs up fossilized manure :P
- Squirtle chases after a dynamite fuse
- Ash, and TR get trapped in the biggest hole ever, and Ash is about to get himself eaten alive
- Charmeleon evolves
- Jigglypuff surprisingly reappears to knock out Aerodactyl back to sleep.
- An egg appears for the first time in the series
- TR once again surrounded by killer pokemon. I love it.