What Pokémon Soulgold changes
How the game plays differently from Pokémon Emerald, then what it does to the Pokémon.
How the game plays
Soulgold is a Johto game built on the pokeemerald-expansion engine by rahtak, growing out of an unofficial expansion port of Heart & Soul and not affiliated with the official Heart & Soul 2.0. It keeps the shape of a traditional run — eight Johto gyms, the Rocket takeover, the Elite Four — and widens almost everything around it: a redrawn Johto with areas the original games never had, nine starters, every Mega Evolution reachable through type-generic stones, Hidden Grottos that reset daily, boss versions of legendary fights that guarantee the catch once beaten, and a Title Defense system so the champion at the end of the League is not always the same one. The deepest change is to battling itself: alongside its ordinary ability, every Pokémon carries innates that are permanently active, so a team read without them looks far easier than it plays. Difficulty and level caps are settings rather than separate patches.
Every Pokémon has innates as well as an ability
A Pokémon here carries its ordinary ability — the one it rolls or has set — and on top of that a set of innates that are always active, all at once, permanently. They are listed on every species page and under every Pokémon on a trainer's team, because a roster read without them looks much easier than it is. This is also why the "compared with the official games" block on a species page leaves abilities out: an official ability that has become an innate here has not been lost.
Normal and Hard are a setting, not a patch
Difficulty is chosen in game. Most trainers have one team, but 83 fights have a separate Hard roster, and each of those pages says which mode it belongs to. Level caps are an option you can switch on as well.
Day and night change what is in the grass
Some maps carry a separate night encounter table. Where one exists it is listed as its own method on the area's page rather than as a second copy of the area, so the day and night tables sit side by side.
Boss Pokémon and guaranteed catches
Some legendary fights are boss battles with more than one health bar and higher stats. Once you beat one, the catch is guaranteed with any ball.
Hidden Grottos, and a Johto that got bigger
Hidden Grottos hold rare items and Pokémon and reset daily. Beyond them the map itself is expanded well past Johto's usual borders, with areas the original games never had.
From the game's own documentation and its published data.
The main changes
- The whole of Johto on the modern pokeemerald-expansion engine, with a fresh tileset and areas well beyond the region's usual borders
- Permanent innates on top of each Pokémon's ordinary ability: 959 of the 959 species in the game carry at least one
- A Hard setting and optional level caps chosen in game rather than as separate patches; 83 fights carry a separate Hard team
- Nine starters, and every Mega Evolution reachable through type-generic stones
- Hidden Grottos that reset daily, boss versions of legendary fights that guarantee the catch, and a Title Defense system at the end of the League
- 132 wild tables with separate night encounters where the game has them, 959 Pokémon, 848 moves and 433 trainer fights
How the Pokémon change
The game leaves the official base stats, types and abilities alone. What it changes is elsewhere: movesets, encounters and trainer teams.