Ritchie reads the episode title
After Richie returns from time traveling, we learn that Nick became the mayor.
Pokémon owned by the Construction Workers are Machoke, Rhydon, Scyther, and Pinsir.
Richie sees a Celebi for the first time.
In the Pokemon Gold/Silver/Crystal,Celebi is in a forest and watches over it. In Pokemon Colosseum, Celebi can purify a Pokemon's heart. However, in this episode, Celebi just travels through time. This shows that Celebi's role changes from time to time, but in all accounts, Celebi is a guardian.
In Other Languages
Italian: Salviamo il Centro Pokémon!
The dialogue where Nurse Joy tells Ritchie about her grandmother's birthday and the anniversary of the Pokémon Center is the same in both versions, but the dubbed English version has Joy mentioning that the Pokémon Center first opened "75 years ago", while the original Japanese version has Joy stating that the Pokémon Center first opened "a long time ago." Though according to the website Pokeani, it was only 50 years ago which would seem to be a better approximation because of Nurse Joy's and Nick's appearances.
After Ritchie and Sparky are taken to the past and the Celebi figurine falls to the floor, a nine-second shot of the empty guest room followed by a shot of Ritchie and Sparky arriving at a green field is removed from the dub.
The banter exchanged between Ritchie, Joy, and Nick is different in both versions; in the English version, Joy says that she wants to travel despite her mother wanting her to run the Pokémon Center when she's older. Ritchie then asks Nick what he does, and Nick answers that he helps his father before getting interrupted by Sparky. In the Japanese version, Joy says that she wants to be a nurse and will starting her training in a year's time. Ritchie asks Nick what his dream is, and Nick responds with "Well, I..." before getting interrupted by Sparky.