The premier set of the Gorgeous Star series began to feature Generation IX Pokémon in earnest and introduced the Terastal mechanic to Pokémon Mezastar. Pokémon with a Terastal mark on their tags could Terastallize when selected to battle; Pokémon in this state could gain boosted bonuses from the Attack Roulette and use any Terastal move detailed on their tags. While not explicitly detailed on tags, a Pokémon's Terastal move type also designated the Tera Type it would change to upon Terastallizing. A Pokémon would remain Terastallized while it could still battle and only one Pokémon could Terastallize per session. Grade 6 Superstar Pokémon Charizard, Meowscarada, Skeledirge, and Quaquaval, as well as Grade 5 Star Pokémon Pikachu all supported the Terastal mechanic in this set.
Legacy tags, aesthetic variants of Grade 6 Pokémon from past sets, continued to be a feature in this set. Mewtwo from the fifth Super Tag set, Zacian and Zamazenta from the first Double Chain set, Zygarde from the second Double Chain set, and Eternatus from the third Double Chain set could be obtained during play starting August 3, 2023. Gorgeous tags (Japanese: ゴージャスタグ) were a new type of aesthetic tag variant to debut in this set, which feature a rainbow Holofoil treatment on the artwork. Pokémon are depicted with a golden aura and tags have the word "ゴージャス" "Gorgeous" on both faces. Gorgeous Pokémon could be encountered during Get in Battle! mode and could be captured in Get Now! mode as per their regular counterparts; they could also be encountered from the launch of the set, unlike the established Legacy Pokémon. Nine Gorgeous Pokémon could be dispensed in total: Charizard, Celebi, Togekiss, Blissey, Togepi, Shinx, Krookodile, Golurk, and Carkol. Opposing Gorgeous Pokémon during Get Time! or Last!! Get Time! would cause Luxury Balls (named Gorgeous Balls in Japanese) to appear on the Poké Ball Roulette.
As with the previous debut set of a new series, all Pokémon Mezastar machines running Gorgeous Star featured updated UI graphics. The train station on the main menu was changed to a more opulent design featuring tilework and chandeliers; the park entrance to Get Now! mode was similarly changed to a more open area with a fountain and could be accessed through a ticket gate. Tags from the Gorgeous Star series featured different background artwork and began a new numbering system prefixed with "4".
Players who used a Memory tag at any time from the set's launch until September 6, 2023 would earn a Weekly Stamp. Using a Memory tag with the same profile in a subsequent week would earn players another Weekly Stamp. Accumulating two of these stamps would unlock a picnic bag Fashion Item for players to customize their avatar. Accumulating four stamps would unlock a Superstar Sensor, five stamps would unlock a Ho-Oh Emblem, and six stamps would unlock another Superstar Sensor. Players with the Ho-Oh Emblem would then have a chance to add the Rainbow Pokémon to their Support Pokémon roster during Get in Battle! mode. Players with Memory tags could also add up to three new Partner Pokémon to their roster: Sprigatito, Fuecoco, and Quaxly. Each Pokémon could be evolved through to their final stage by earning in-game Star Points. Double Star Points could also be earned in two stints over the course of the set: between July 27 and August 9, 2023 and between August 31 and September 13, 2023. People with a Mezastar Club account could redeem digital tickets at any time for the duration of this set and scan them on Mezastar machines to unlock exclusive features. These included a Support Pokémon Ticket for a Sylveon and a Present Ticket to unlock a set of festive Fashion Items comprising yukata, geta, and uchiwa in conjunction with Tanabata, which was observed during the set's operation. A limited Present Ticket for a set of diving gear Fashion Items could be redeemed through the club between July 17 and 30, 2023.
The Trainer and Battle lineup for this set included two returning Trainer classes in Waiter and Bug Catcher Girl, two new Trainer classes in Artisan and Hairdresser, and a new Star Trainer named Sasura. Mezastar Club members could redeem Battle Tickets for each opponent and challenge them to unlock new customization options for their avatar. As part of a tie-in with the anime, characters from Pokémon Horizons: The Series could also randomly challenge the player as a Trainer and Battle opponent. These comprised Rising Volt TacklersLiko, Roy, and Friede, as well as Explorers Admin Amethio. While challenging the anime-related opponents did not offer trophies or Fashion Items, players were given the option to dispense a tag featuring one of their Pokémon after a battle. Between July 20 and August 16, 2023, players could challenge Star Trainers Tarmo and Ishuta in a Trainer Tag Battle. Those that managed to defeat the pair would each unlock a formal jacket Fashion Item. Mezastar Navigators Masato and Sakura could also be challenged as Trainer Tag Battle opponents for a limited time as part of the ranked Masato & Sakura's Powerful Tag Battle campaign. Pairs that defeated Masato and Sakura in battle would unlock Superstar tag sunglasses Fashion Items for their avatars. Players with the top 100 scores following the end of the campaign also won a certificate. The campaign ran from August 20 until September 13, 2023.
From July 6, 2023, one entertainment center from each of Japan's 47 prefectures was designated a "Mezastar City". These chains, which comprised Molly Fantasy, youme Town, and Namco arcades, contained Mezastar machines running a Mezastar TV Edition mode, which could be identified by an additional graphic on the start screen. Mezastar Navigators Masato, Ai, Sakura, and J (as well as some of their other personas) would appear in place of the usual characters providing guidance, with their own unique dialogue. Graphics of the Mezastar Navigators would also pop up from the bottom of the screen intermittently to "cheer" the player.