The fourth Grand Rush set includes a selection of Pokémon primarily from GenerationsIV and V, a handful of which make their Pokémon Ga-Olé debut. Several high-grade Pokémon also continued to support the Double Rush and Combo Rush mechanics that were the focal point of the series. This set featured a number of courses on which Pokémon with the Double Rush ability could be encountered. SinnohLegendary PokémonDialga, Palkia, and Giratina were among the first, the latter consecutively in its Origin and Altered Formes on two dedicated courses, as well as the Eon Pokémon Latias and Latios, which have the ability to Mega Evolve. Unlike prior Grand Rush sets, certain courses featured the Ultra Beast Appears! icon from the launch of the set. By playing any of these courses, players would have the chance of encountering Ultra BeastsBlacephalon and Stakataka, both Grade 5 Pokémon with the Double Rush ability. Pokémon supporting the Combo Rush mechanic in this set include the final evolutions of the Generation IV startersTorterra, Infernape, and Empoleon, and the final evolutions of the Generation V starters Serperior, Emboar, and Samurott. Each Pokémon within these groups of three can Combo Rush with one another. Analogous Pokémon Electivire and Magmortar can also Combo Rush with each other.
As part of a tie-in with the anime, Ash and Goh were integrated into a number of gameplay features. Goh replaced the Experienced Trainer that would normally appear in Golden Chance as well as Mister Trade who would normally appear in Trade Chance! Ash replaced the Experienced Trainer that offers consolation disks if no Pokémon were captured during Get by Battle mode. The two were also featured as opponents in Trainer and Battle Mode, which was available to challenge from February 24, 2020. This was considerably earlier into the set's duration compared to other sets—the fourth Ultra Legend set, which also featured special opponents in Trainer and Battle Mode, shares this trait. The lineup included 1 new Trainer class in addition to Ash and Goh, who had their hometown as part of their name instead of "Pokémon Trainer". Ash could be challenged after defeating the other Trainer and Battle Mode opponents. Promotional disks could also be dispensed for an additional ¥100 following battles with Goh or Ash, with 'WINNER' versions available to players who successfully defeated their teams. Players facing Goh could receive a Scorbunny disk, while those facing Ash could receive a Mew disk or a Lugia disk.
Haxorus and Dusk FormLycanroc were added as Support Pokémon from this set. Players registering a Ga-Olé Pass for the first time would automatically receive Haxorus as a Support Pokémon as part of the Pokémon Ga-Olé Welcome Campaign.
A number of promotions and events that were to be held throughout this set's duration were canceled due to the COVID-19 pandemic, the first of which was a Ga-Olé Ticket giveaway scheduled to begin at Pokémon Centers from February 28, 2020. This ticket would have unlocked the Legendary Pokémon Gathering Course (Japanese: でんせつのポケモン だいしゅうごうコース), intended to be playable from the giveaway start date until May 31, 2020. Its postponement was announced on the Ga-Olé website on February 28 and confirmation of its cancellation was announced on April 14. Further instances of the CoroCoro Dream Fight! Rayquaza Super Challenge were scheduled to be held at stores across Japan between March 14 and April 5, 2020, which would have given players another opportunity to earn promotionalRayquazadisks. Its cancellation was announced on February 28. The Pokémon Ga-Olé Get Campaign associated with this set, due to begin on March 12, 2020 at participating Molly Fantasy and PALO entertainment centers across Japan, was canceled on March 11. This course would have given players the opportunity to catch and earn a promotional Zygarde disk. The release of the fifth Grand Rush set was also pushed into June from its intended launch date of April 23, 2020. As a result, courses from this set that were due to expire on April 22 remained playable until the day before the fifth set's eventual release.
Dialga & Palkia Double Rush Course
Playable at set launch
Giratina Double Rush Course: Origin
ギラティナ ダブルラッシュコース オリジン
Playable at set launch to March 18, 2020
Let's Begin Ga-Olé! Course
Playable at set launch
Its Z-Move! Xerneas & Yveltal Course
Playable from March 12, 2020
Giratina Double Rush Course: Altered
ギラティナ ダブルラッシュコース アナザー
Playable from March 19, 2020
Double Rush One After Another Course
Playable from March 26, 2020
Available for Pokémon Ga-Olé Members to redeem from February 13, 2020 for 1,000 Member Points
Get It! Deoxys (Attack Forme) Course
Playable from February 13 to June 7, 2020
Available as an insert in the April 2020 issue of CoroCoro Ichiban!, released on February 21, 2020
Get It! Ho-Oh & Marshadow Course
Playable from February 21 to June 7, 2020
Mega Latias & Mega Latios Double Rush Course
Playable from February 27 to April 8, 2020
Available as an insert in issue 67 of Pokémon Fan, released on February 28, 2020