This is a custom Pokémon game based on the Pokémon Crystal disassembly.

My goal is to create what the title says: an improved, polished version of Pokémon Crystal. It fixes bugs, takes into account the official game changes since 2001, and adds some new ideas of my own. Many features restore what was removed from R/B/Y, or original to HG/SS.

I've had vague plans to make a Pokémon game for years. I'm very impressed by the effort that's gone into disassembling Pokémon Crystal and making the code so well-organized. Thanks to making it open-source (and to the ROM hackers that inspired me), I'm finally making this game a reality.

There are many ways to create games but the way we work at Game Freak may be a little different from other companies. That is, we constantly change and tweak what we have come up with. To make a fun game even more fun and polish it up, we take what we have made and start thinking about it from scratch. And to make the game the most fun to play we make endless changes and tweaks no matter how long it takes. It may not be the best way, but I think these tweaks are important to make our games fun and better.

— Junichi Masuda, "HIDDEN POWER of masuda No. 7"

The most recent version is 2.2.0 as of September 20, 2016. The changelog lists all changes since then.

To play, download the .ips patch file, and use a tool like Lunar IPS (for Windows), MultiPatch (for OS X), or UniPatcher (for Android) to apply the patch to a default Crystal ROM.

This is the ROM you should use:

• Pokémon - Crystal Version (UE) (V1.0) [C][!].gbc
  (md5: 9f2922b235a5eeb78d65594e82ef5dde)

It's identical to the one built by the pokecrystal project.

If you want to do a Nuzlocke Challenge, check out Nuzlocke mode in the Option menu!

There are two patches for Polished Crystal. The "faithful" patch does not change any Pokémon base stats or move attributes beyond the updates in Gen VI. The regular patch has some custom changes for more diverse and viable Pokémon.

• Pokémon Polished Crystal 2.2.0
  (IPS patch file md5: 043769cc7e1a0ccfad635ff72b0ab8d0)
  (Patched GBC ROM md5: 9d3a3026bc3730cdf5d813b0bfe49697)
• Pokémon Polished Crystal (Faithful) 2.2.0
  (IPS patch file md5: 5cbd4bef0e03936291f40b14c75b47d3)
  (Patched GBC ROM md5: cb5921d6646d2adfd302d8957e5e39af)

A full list of features is in FEATURES.md. Some highlights:

• 253 Pokémon, including some new evolutions.
• 48 new moves.
• 65 TMs and 21 move tutors.
• Many new mechanics, including the Fairy type, Physical/Special split, Natures, unlimited TMs, Running Shoes, and continuous Repel.
• New maps: some restored from R/B/Y, some devamped from HG/SS, and some original.
• New characters, including Lorelei and Agatha from R/B/Y, Lyra and the Team Rocket Executives from HG/SS, and others.
• More post-game content, like Gym Leader rematches and an event after the battle with Red.
• An improved level curve with steadily increasing challenges throughout the game.
• Music and graphics devamped from other versions.
• Nuzlocke mode in the Option menu, enabling the basic rules of the Nuzlocke Challenge.

You can post questions or comments on any of these sites. But please read the FAQ first if you have a question.

• Discord
• Skeetendo
• PokéCommunity
• Romhack.me
• /r/PokemonROMHacks
• Nuzlocke Forums
• Pokémon Hackers Online