Ghost Grey: What's Different From Vanilla

Short answer: Ghost Grey is a binary FireRed hack running a modern engine, and it is not a cosmetic reskin. It ships its own type-effectiveness table with nine deviations from the standard Gen 6 chart, removes EVs and IVs entirely, has no breeding, and expands the dex to 291 species. Everything on this page is read out of the ROM itself, not copied from the release post.

What is different, in one screen

• Engine: Pokémon FireRed (USA) Rev 0 with the HUBOL DPE + CFRU rombase -- an expanded species/dex engine bolted onto FireRed's, not vanilla FireRed.
• Types: 19 in the game's table (the standard 18 plus a typeless entry), with nine matchups changed from the chart you know.
• Stats: no EVs, no IVs, no Hidden Power. Every species' EV yield in the ROM is empty.
• Breeding: the author states there are no eggs and no breeding, so offspring mechanics never come up.
• Pokédex: 291 species, over 200 of them Ghost-type, including 120+ original regional variants.
• Moves: 484 published, including new moves written for the hack.
• Items: 314, with unlimited-use TMs and forgettable HMs.
• Quality of life: an unlimited Rare Candy key item, a dedicated grinding area, a purchasable Exp. Share from the first city.

The engine underneath

Ghost Grey is a binary hack, not a decompilation project. It patches Pokémon FireRed (USA) Rev 0 (CRC32 DD88761C) up to a 32 MB ROM, and the patched build is built on the HUBOL DPE + CFRU rombase -- a drop-in engine that expands the species table, adds newer abilities and moves, and brings the battle engine forward.

Two practical consequences:

• New Pokémon live in expanded tables, not replacements. The engine inserts species rather than overwriting FireRed's 386, which is how the hack carries 291 documented species with original art.
• Mechanics are FireRed-shaped but modern-behaving. The physical/special split, the added Fairy type and the newer abilities all behave the way the feature list says -- but the underlying formulas stay Gen 3, which is why things like the damage formula need their own reference if you're doing exact calculations.

PolishedDex documents Ghost Grey from the v1.0.4 patch (CRC32 737A7A12). If the author ships a new patch, the whole dataset here is re-extracted and re-verified against the new build.

Types: the hack rewrote the chart

Ghost Grey's effectiveness table is not the standard one. We diff the ROM's own table against the modern (Gen 6) chart, treating any matchup the ROM omits as neutral. Nine matchups differ:

Three of these are the changes the author advertises: Steel resists Ghost and Dark again (the pre-Gen 6 behaviour), Psychic is no longer hit super-effectively by Ghost, and Fairy only resists Dragon instead of being immune to it. Our table agrees with all three.

The other changes aren't in the release notes. The two that matter most are the first two rows: Normal and Fighting moves now connect with Ghost-types. In a hack where most of the dex is Ghost, keeping those immunities would have made a large slice of the movepool dead weight, so the change reads as deliberate balance -- but it is not documented in the release post, and it is the single biggest way a trainer fight here differs from muscle memory.

One discrepancy worth knowing: the release notes describe Ghost-vs-Ghost as "1.5× instead of 2.0×", but the ROM's table only carries 0×, 0.5×, 1× and 2×, and it lists Ghost-vs-Ghost as neutral. Either the 1.5× lives in the damage formula rather than the type table, or the note is approximate. We report what the table says and flag the difference rather than smoothing it over.

You can see the full rendered table -- all 19 types, every matchup -- on the Ghost Grey type chart.

No EVs and no IVs

This is the cleanest of the changes, because the ROM itself proves it: every species' EV yield in the extracted data is empty. Nothing grants effort values from battle or from items, so a Pokémon's stats at a given level are fixed by its species and level alone.

Combined with the release notes -- all Pokémon have 0 IVs and cannot gain EVs, and Hidden Power is absent -- the practical upshot is:

• No EV training, no spreads, no 252/252/4. If you're used to optimising, that entire layer is gone.
• No Hidden Power, so no Hidden Power typing puzzles and no Hidden Power coverage moves.
• Team strength is level, species, moveset and items -- a simpler, flatter power curve than a mainline game.

If you're coming from a game with full stat investment, this is the mechanic most likely to catch you out, because it changes what "a strong Pokémon" even means here.

Breeding

The release notes state there are no eggs and no breeding. The extracted data still carries an egg group and gender ratio for each species, because that metadata comes with the species table -- but treat those fields as reference only, not as a breeding system you can use. There are no egg moves to plan around, no natures to inherit from parents, and no IV inheritance to chase.

The Pokédex: 291 species

PolishedDex publishes 291 Ghost Grey species, each with base stats, typing, abilities, the moves it learns and where it can be found. Over 200 of them are Ghost-types, including more than 120 original regional variants that don't exist in any mainline game -- so the Pokédex is not a lookup for a game you already know, it's the primary reference for a dex you can't get anywhere else.

The in-game dex is improved too: it shows a Pokémon's available abilities and base stats directly, so you can evaluate an encounter without leaving the game.

Moves: 484, with new ones written for the hack

The hack publishes 484 moves, and it doesn't leave the familiar ones alone:

• Dark Pulse and Crunch are cut to 70 base power (from 80), which softens the Dark-type options that would otherwise dominate against a Ghost-heavy field.
• New moves exist that don't come from any official game -- among them Purify (a physical Psychic move that applies Foresight on hit), Shatterpoint (a physical Psychic move standing in for Brick Break), Soul Shift (a Psychic-type U-turn) and Jumpscare (a Ghost-type Fake Out).

Browse the full move list for types, power, accuracy and learnset, and remember when you're theorycrafting that the type chart above applies to all of it.

Items and quality of life: 314 items

314 items are documented, and the hack leans hard on making the game fast to play:

• Unlimited-use TMs -- no more hoarding a one-shot TM.
• Forgettable HMs -- HM moves can be deleted, so an HM mule isn't a permanent tax on a team slot, and the HMs themselves were buffed to be usable in battle.
• An unlimited Rare Candy key item, so levelling isn't gated behind grinding.
• "The Fight Club", a dedicated grinding area for players who would rather train than wander.
• A purchasable Exp. Share, an ability-changing item and an exp-boosting item, all available as early as the first city.
• Items from later games -- Choice Scarf, Eviolite and others -- appear again.

The item list covers what each one does and where it comes from.

How PolishedDex documents Ghost Grey

Every number on this page comes from the ROM, not from the release thread:

• 291 species, 484 moves, 314 items, 527 trainers, 137 abilities and 83 locations are extracted from the v1.0.4 binary and published as Pokédex, moves, items, trainers, abilities and locations.
• Type matchups, EV yields and the Pokédex all come from the game's own tables, which is why this page can disagree with the release notes in places and say so.
• We re-run the extraction when the author ships a patch, so version drift is a maintenance task here rather than a permanent error.

What this page does not claim

• It is not a walkthrough. Ghost Grey has no published text walkthrough anywhere; the story beats and specific route orders are not something we assert here.
• The release notes are treated as claims, not data. Where they conflict with the extracted tables, we show the table and flag the difference -- the Ghost-vs-Ghost case above is the clearest example.
• Numbers change with patches. The counts on this page are pinned to v1.0.4 and will move when the ROM does.

Where to go next

• Ghost Grey Pokédex -- every species, with stats, abilities and locations
• Ghost Grey type chart -- the full 19-type table this page summarises
• Moves and Items -- the full movepool and every item
• Gym Leaders -- badge order, teams and levels, read out of the ROM
• Champion Battles -- the two champions and their starter-dependent leads