Similar to how Naughty Dog pushes the limits of graphics on PlayStation platforms today, Rare filled that same position by breaking new ground back in the Nintendo 64 era. Just when the worlds of Banjo Kazooie seemed gargantuan and extremely detailed for the time, the company blew expectations out of the water with Donkey Kong 64. The game featured easily some of the best graphics on the system, while simultaneously rendering absolutely massive environments to explore (that still remain fairly big, even by today's standards).
Continuing this trend of constantly outdoing past efforts, one of the final games Rare had in development for the N64 was Dinosaur Planet, a 3D adventure similar to The Legend of Zelda: Ocarina of Time. Although nearly complete, Nintendo's Shigeru Miyamoto instructed Rare to make creative changes to the project and Dinosaur Planet eventually changed into StarFox Adventures for the GameCube. Had Dinosaur Planet stuck to its original plan and been released for the N64 however, its many features and technical aspects could have made it the most ambitious title on the console.
Grand Scale Adventure
Many of Rare's past games were already lengthy quests. Considering those titles were predominantly platformers, and Dinosaur Planet was opting for an adventure more in line with The Legend of Zelda series, this prehistoric journey was elevated to a whole new scale. Firstly, the player would have access to two different protagonists, each with specific skills and weapons to complete a wide variety of objectives. These characters would additionally have their own interactive partner to assist during the quest, similar to Tricky in StarFox Adventures.
Many of the environments are also vast and fully explorable, with hidden secrets and NPC's to interact with as the game progresses. Much of the events and locations in the game actually remain very similar to what was eventually experienced in StarFox Adventures. Even that game is considered one of the most technically impressive GameCube titles, despite being initially designed on a console with technology already several years old by this point.
Impressive Graphics
While it may not look like much by today's standards, for what the Nintendo 64 was capable of at the time, Dinosaur Planet looked to be a huge leap from a graphical standpoint. Similar to other N64 games that used the expansion pak to push the limits of the console, Dinosaur Planet was on pace to rival the likes of The Legend of Zelda: Majora's Mask in terms of delivering not only a massive world to travel in, but one that was graphically rich as well.
Character models looked well-detailed for the time, with expressive features and a solid range of animations. Environments featured stunning particle effects like snow falling in a colder region or thick rainfall in a grassland. Rare was definitely aiming to push the envelope with its swansong on the N64, attempting to outshine past efforts and stand with some of the most graphically impressive N64 games like Perfect Dark and Star Wars: Rogue Squadron.
Fully Voiced Dialogue
While it may seem bizarre to praise nowadays, an entire game being fully voice acted wasn't as common a feature back in the late 90's and early 2000's (especially on the N64). The maximum space for an N64 cartridge was 64MB, a small size for developers to store data, so small in fact that the entire N64 library can fit on one Switch cartridge nowadays.
For the sake of comparison, the only other major N64 titles to feature voice acting aside from Rare's raunchiest title Conker's Bad Fur Day are Star Fox 64 and Resident Evil 2. Even those pale in comparison to its extensive use in the game about a drunken squirrel. To see such a balancing act of impressive graphics, huge game worlds and full voice acting with character mouths actually moving would've been an unprecedented achievement for this era of gaming.