How to beat every Pokémon game

Catch a Shroomish in Petalburg Woods — Absorb sweeps her Geodudes and Nosepass.

• Petalburg Woods: help the Devon Researcher vs. a Team Aqua/Magma grunt → he gives you a Great Ball.
• Catch: Shroomish (Grass), Wurmple (evolves to Beautifly or Dustox by chance), Taillow (great Flying).
• Roxanne: Geodude x2 (Lv. 12) → Nosepass (Lv. 15, Rock Tomb + Harden + Tackle).
• Counters: Mudkip (Water Gun), Shroomish (Absorb), Lotad if Sapphire.
• Reward: Stone Badge + TM39 Rock Tomb.

Use a Taillow or any Psychic/Flying-type.

• Mr. Briney sails you to Dewford. Granite Cave (with Flash) — get HM05 from a researcher inside; Steven gives you the Letter on B2F.
• Catch: Makuhita (yourself for Fighting), Aron (Steel/Rock — fantastic).
• Brawly: Machop (Lv. 16) → Meditite (Lv. 16) → Makuhita (Lv. 19, Arm Thrust + Bulk Up).
• Counters: Taillow (Wing Attack), Ralts (Confusion), Beautifly.
• Reward: Knuckle Badge + TM08 Bulk Up.

Catch a Geodude or Marill — Ground-types are immune to Electric.

• Slateport: deliver the Devon Goods to Capt. Stern at the shipyard — a Magma/Aqua grunt blocks the museum.
• Trick House on Route 110 opens after Stone Badge. Solve the puzzle for prizes.
• Cycling Road shortcut needs the Bicycle (free at Mauville's bike shop).
• New Mauville (post-Wattson sidequest) — need to fix the generator: yes/no/no/yes/yes route.
• Wattson: Voltorb (Lv. 20) → Electrike (Lv. 20) → Magneton (Lv. 22) → Manectric (Lv. 24, Quick Attack + Thunder Wave + Shock Wave).
• Counters: Marshtomp (already Lv. 25+ish), Geodude (Magnitude), Numel.
• Reward: Dynamo Badge + TM34 Shock Wave.

Bring a Marill, Wingull, or Numel-evolution. Avoid Grass.

• Mt. Chimney: stop Team Magma/Aqua at the summit — Maxie/Archie boss fight (Mightyena + Camerupt or Sharpedo).
• Jagged Pass → Lavaridge. Hot Springs heal your team for free.
• Flannery: Numel (Lv. 24) → Slugma (Lv. 24) → Camerupt (Lv. 26) → Torkoal (Lv. 29, Overheat + Attract + Sunny Day).
• Counters: Marshtomp/Wailmer (Water Gun), Geodude (Rock Tomb).
• Reward: Heat Badge + TM50 Overheat.

Your dad! Use a Fighting-type — Makuhita/Hariyama from Granite Cave is ideal.

• Petalburg Gym has 8 sub-rooms — pick a path: Speed, Accuracy, Recovery, etc. The straight path is fastest.
• Norman: Spinda (Lv. 27) → Vigoroth (Lv. 27) → Linoone (Lv. 29) → Slaking (Lv. 31, Facade + Yawn + Faint Attack + Slack Off).
• Slaking has Truant (skips every other turn) — set up X-Attack on his lazy turn.
• Counters: Hariyama (Arm Thrust), Combusken (Double Kick), Machop.
• Reward: Balance Badge + TM42 Facade. Now Surf works outside battle.

Magneton, Manectric, or any Rock/Ice attacker. Catch a Tentacool in the meantime.

• Route 119: invisible Kecleon blocks the bridge — Devon Scope (from Steven on Route 120) reveals it.
• Catch Feebas in Route 119 (only 6 specific tiles per save — fish, fish, fish). Evolve via Beauty contests/Prism Scale.
• Winona: Swablu (Lv. 29) → Tropius (Lv. 29) → Pelipper (Lv. 30) → Skarmory (Lv. 31) → Altaria (Lv. 33, Aerial Ace + Earthquake + Dragon Dance).
• Counters: Manectric (Thunderbolt), Magneton, any Rock-type with Rock Tomb.
• Reward: Feather Badge + TM40 Aerial Ace.

First double battle gym. Bring 2 strong attackers and avoid Earthquake (hurts your own ally).

• Mossdeep Gym puzzle: rotating arrow pads. Step on each only once or you'll loop back.
• Tate & Liza: Lunatone + Solrock (both Lv. 42, Calm Mind + Psychic + Sun/Moonlight + Earthquake).
• Strategy: lead Sharpedo (Crunch) + Manectric (Thunderbolt). KO Solrock first (water-weak), then Lunatone.
• Avoid Earthquake — friendly fire in doubles. Use single-target Dark/Ghost moves.
• Reward: Mind Badge + TM04 Calm Mind. Dive HM unlocks underwater routes.

Need 8th badge from Wallace/Juan after the Kyogre/Groudon climax. Electric or Grass moves.

• Story climax in Sootopolis: Cave of Origin — Kyogre (Sapphire) / Groudon (Ruby) awakens. Catch with Master Ball or Timer Ball at low HP + status.
• Sootopolis Gym puzzle: melt thin ice tiles by stepping on them — don't crack the same tile twice or you fall through.
• Wallace (Ruby/Sapphire): Luvdisc → Whiscash → Sealeo → Seaking → Milotic (Lv. 43, Recover + Surf + Ice Beam + Toxic).
• Counters: Manectric (Thunderbolt), Roselia (Mega Drain), Sceptile.
• Reward: Rain Badge + TM03 Water Pulse.

Sidney (Dark) → Phoebe (Ghost) → Glacia (Ice) → Drake (Dragon) → Wallace/Steven (Champion).

• Sidney: Mightyena/Shiftry/Cacturne/Crawdaunt/Absol — Fighting + Bug.
• Phoebe: Dusclops x2/Banette x2/Sableye — Dark moves (Crunch).
• Glacia: Sealeo x2/Glalie x2/Walrein — Fighting + Steel + Electric.
• Drake: Shelgon/Altaria/Flygon x2/Salamence — Ice Beam ohkos all but Altaria (use Ice + Dragon).
• Steven (RS): Skarmory/Claydol/Aggron/Cradily/Armaldo/Metagross. Bring Fighting (Hariyama Cross Chop) + Fire (Blaziken Blaze Kick) + Ground.