Back when the Pokemania was at an all time high in the 2000s, Nintendo was about to release their latest Pokemon main movie, titled "Pokemon 2000", and to release it in North America, Nintendo contracted Warner Bros. as the main distributor for the movie in the region, all with permission and license to create promotional material for the movie. One of these materials was a 3D game for the franchise now known as "Pokemon 2000 Adventure"
Warner Bros. on its own contract a gaming company at the time known as Cyberworld, who had experience with 3D games for other franchises, and they developed some sort of pseudo-first-person game with a 3D environment with 2D sprites in it, similar to popular games of the 90s like Doom or Duke Nukem 3D, which could be downloaded and ran on a web browser. The game became wildly popular, far exceeding Warner Bros. expectations, and both Nintendo's expectations and contract scope.
To sum the whole ordeal that went through, Did You Know Gaming (DYKG) got in contact with one of Cyberworld's developers, Eddie Ruminski, and he explained the whole situation, detailing that the game had a million downloads in the span of a month, making it Cyberworld's most popular game to date, and Nintendo sent a C&D, with them claiming Warner Bros. breached the contract for the promotional material, effectively killing the project.
The game starts with Prof. Oak claiming there's some problems in the land, and the player should choose between 3 Pokemon teams and a difficulty. Then the player gets to delve and explore the three islands seen in the movie in a 3D environment, with the exploration sometimes being hindered by environmental hazard that your Pokemon team can help you traverse or get past. The main goal of the game is to get each one of the 3 legendary birds' (Articuno, Zapdos and Moltres) Ancient Spheres. Finishing the game also gives the player a ranking at the end, going from Gold, Silver and Bronze. The ranking system, paired alongside the different teams added some replayability to the game, which made it more interesting for Pokemon fans.
Those interested in playing "Pokemon 2000 Adventure" can try it out right now through the archived website for it on Archive.org. Be aware that the game does requires some work and setup to get it working, but the instructions to get it working are fully explained in the Archive.org description for the game. Also, be sure to get the preserved game and spread the word about it around, just in case the game becomes inaccessible yet again due to "unforeseen circumstances".
Thanks to the great work and effort of the people involved in this endeavor, like DYKG, Eddie Ruminski, and developers DoomTay and rufus10, who worked on getting the game working on modern internet setups.
Pokemon 2000 Adventure Archive.org Website