X and Y introduced 72 new Pokémon species, and added new features including the new Fairy-type, character customisation, updated battle and training mechanics such as "Mega Evolution", and completely rendered polygonal 3D graphics as opposed to the sprites used in previous generations.

As of 31 March 2023[update], a combined total of 16.68 million copies have been sold worldwide, making X and Y the second best-selling games on the system after Mario Kart 7.

[3] Pokémon X and Y are the first titles in the main series presented in fully 3D polygonal graphics, allowing for more interactivity with the overworld and more dynamic action during battles.

[4] Players are also able to customise their Pokémon trainer's appearance, choosing gender, skin tone and hair colour at the start of the game, and can later acquire outfits and accessories in-game to change their character's look.

These applications, announced for release on 27 December 2013, were postponed to 5 February 2014, due to the volume of traffic on the Nintendo Network service.

Similar to previous Pokémon games, X and Y both follow a linear storyline whose main events occur in a fixed order.

Thereafter, they encounter Sina and Dexio, assistants of Sycamore, who brings them to the professor himself; however, once in Lumiose City they discover the area to be suffering from a partial power outage.

Upon meeting Sycamore in Lumiose City, the player is informed of Mega Evolution and he requests they travel across Kalos and uncover the mysteries behind it.

Before leaving Lumiose City, the player encounters an imposing man named Lysandre who desires a more beautiful world.

Continuing their journey, the player encounters the villainous Team Flare, whose goals at first seem to be geared towards making money off of Pokémon.

Later encounters with Team Flare reveal their true goal to be the annihilation of humanity to return the world to a pristine, more beautiful state.

Following hints from friends and locals, the player discovers Team Flare's secret lab under a café in Lumiose City where they formally meet a 9-foot (2.7 m) tall man named AZ;[22] he is revealed to be the 3,000-year-old king who once used the "ultimate weapon"—the same device and weapon of mass destruction Lysandre plans to use—which utilized energy from the legendary Pokémon Xerneas or Yveltal[nb 2] to end a war in Kalos.

This war 3,000 years ago set in motion the events necessary to create Mega Evolution by inadvertently infusing excessive energy into an asteroid.

[23] Alongside Shauna and Calem or Serena, the player sets out to stop Team Flare and Lysandre at their second base in Geosenge Town, the location of the ultimate weapon.

They capture the legendary Pokémon and proceed to bring an end to Lysandre's plans after defeating him in battle one final time.

With the defeat of Team Flare, the player resumes their journey and obtains their eighth and final Gym Badge, enabling them to challenge the Elite Four—the most powerful trainers in Kalos.

Masuda expressed that this effort proved exceptionally difficult as the names have to feel fitting to their physical appearance and not infringe upon any rights.

[34] The game's score was composed by Shota Kageyama, Minako Adachi, Hitomi Sato, Junichi Masuda, Go Ichinose, and Morikazu Aoki.

During an interview with Famitsu magazine, Masuda stated that the Japanese harp was used in place of an accordion in certain situations to avoid giving off excessive French vibes.

[36] The official soundtrack consisting of 212 songs, titled Nintendo 3DS Pokémon X-Y Super Music Collection[b], was released on 13 November 2013.

[41] Jim Sterling of Destructoid praised the music as "utterly lovely", noting "the quieter tunes are legitimately beautiful".

[46] A special Nintendo 3DS XL depicting Xerneas and Yveltal in their Shiny forms was released in North America and Europe on 27 September 2013, and in Japan on 12 October 2013.

Japan also received a premium gold version depicting Xerneas on the front, and Yveltal and the three starters on the back with either X or Y pre-installed.

[51] For a limited time starting from the game's release on 12 October 2013, until 15 January 2014,[52] players could download a special Torchic, possessing its hidden ability "Speed Boost" and a Blazikenite that allows players to utilize the new Mega Evolution game mechanic to evolve Blaziken to Mega Blaziken.

[60][2][59] Edge magazine reviewers described the visuals as "rich in detail and flavour, from the stately majesty of the affluent areas to a dilapidated, overgrown hotel whose only guests are squatting punks".

[59] Simon Parkin of Eurogamer similarly complimented the game's "smooth and natural" transition to 3D, declaring that "Pokémon X & Y is the finest expression of Satoshi Tajiri's obsessive vision yet.

"[60] Matt Kamen of The Observer praised the new gameplay mechanics and the graphical and audio improvements, and deemed the games to be "the series' zenith".

He also praised the faster pace of the early game, with X and Y providing a wide range of Pokémon to catch within the first hour of gameplay.

[2] While Game Informer reviewer Kyle Hilliard found the title's gameplay additions to be mostly positive, "[making] everything more inviting, attractive, and fun", the magazine also felt that they ultimately did not "break the mold" of what players expected from the franchise.

"[60] Conversely, Edge claimed some of the series' "original magic had been lost across so many iterative updates" and criticized its unsteady framerate in 3D mode.