Pokémon Legends: Arceus is a game in the longstanding Pokémon series of role-playing games where you collect and battle Pokémon. Like the other games, you compete in turn-based battles and try and collect as many Pokémon as you can. Arceus, however, also expands the series in new and unique ways; this is the first Pokémon game with a vast, expansive open world to explore, and changes to the way you fight, catch and use the many Pokémon on offer create a more immersive, varied and strategic game.

Set in the distant past, in the Hisui region, which eventually becomes the Sinnoh region where the Pokémon Diamond, Pearl and Platinum games, along with their remakes, take place. Unlike the previous games, where people and Pokémon have coexisted for centuries, most of the people you meet are ignorant, and in many cases fearful, of the Pokémon of the land. It's up to you, with the help of Galaxy Team's Survey Corps to complete the first-ever Pokédex by capturing one of every species. Along the way, you face off against powerful alpha and noble Pokémon, and even a dangerous rift in spacetime itself.
Whereas other Pokémon games have you entering turn-based battles, weakening the Pokémon and then catching them, here, you have the chance to catch a Pokémon without even battling it, by sneaking up behind it and using a well-timed throw, or distracting them with a lure. Battles, too, are different: while they are still turn-based at their core, you have the choice between using more powerful versions of moves more frequently or more powerful versions at the expense of speed, allowing an opportunity for opponents to counter. This all results in a more skill-based experience than the previous games, where you have the opportunity to employ multiple different tactics. You can also complete side quests that reward you with valuable items or money in the town, which is the hub for all your surveying expeditions into the varied and unique climates of Hisui.
It's a unique game in the series, that retains the essential elements of Pokémon games such as battling and collecting, but changes the formula first introduced in 1996 by adding new mechanics and changing existing ones, which makes for a more skill-based, exploratory and novel addition.