Pokémon Red and Blue/Unused Move Data
This is a sub-page of Pokémon Red and Blue.
There exists an unused entry between Fly (HM02) and Surf (HM03) which points to an empty string in the field move name table. It has an ID of 0xB4 (180), whereas the highest valid move ID is 0xA5 (165), though this isn't surprising given how much the move roster was reworked during development. Interestingly enough however, found in the games' leaked source code under SHINKA.SAV is a file which lists a whopping 237 move IDs, which would expand up to 0xED. The source code also specifically names this unused field move, with it being "Mega Fire", a precursor to the move "Fire Blast". Furthermore, while SHINKA.SAV does not list the names of the moves it references, 0xB4 is surrounded by signature moves, in a rather finalized order, one which places it in a sensible spot which confirms that it actually is the mystery scrapped HM, only using an earlier internal name.
We can then infer that Fire Blast was originally an fire-based field move before being downgraded to a regular move, though this doesn't give us any actual information regarding its original in-game use. Its removal may have been anything from it being redundant, to the devs not wanting to promote the use of fire as a problem-solving method.
Dragon Type's Effectiveness
The Dragon type is set to deal super-effective damage to itself in Generation I, just as it does in every subsequent generation; type matchup charts in guides at the time even included this particular type matchup! However, the only Dragon-type move in Generation I is Dragon Rage, which ignores type effectiveness modifiers completely and always deals a fixed 40 HP of damage. As a result, this behavior is never seen in regular gameplay during this generation.
Struggle is a move which cannot be learned during regular gameplay. It is only used when the user's Pokémon attempts to attack but has no available PP for any move left (note that in-game Trainers cannot run out of PP in Generation I). Regardless, the default total PP data for Struggle is set to be 10, though there is a special handler for Struggle such that its remaining PP does not decrement since it is never supposed to be an actual move in a Pokémon's moveset.
The default total PP for Struggle was changed to 1 in Generation II, and remains that way in all the main-series handheld Pokémon games as of Generation V.
There are a handful of effects in the English Red and Blue which aren't used by any valid move, although some of them are used by the TM(xx) and HM(xx) glitch moves. Note that in the Japanese versions, effect 23 (30.1% freeze chance) was used because the effect was originally assigned to Blizzard.
|01||Puts enemy to Sleep.|
|0C||Raises Speed by 1 stage.|
|0E||Raises Accuracy by 1 stage.|
|15||Lowers Special by 1 stage.|
|17||Lowers Evasion by 1 stage.|
|1E||Attacks for 2-5 turns.|
|23||30.1% chance of freezing the opponent.|
|36||Raises Accuracy by 2 stages. (probability=hit chance)|
|37||Raises Evasion by 2 stages. (probability=hit chance)|
|3A||Lowers Attack by 2 stages. (probability=hit chance)|
|3C||Lowers Speed by 2 stages. (probability=hit chance)|
|3D||Lowers Special by 2 stages. (probability=hit chance)|
|3E||Lowers Accuracy by 2 stages. (probability=hit chance)|
|3F||Lowers Evasion by 2 stages. (probability=hit chance)|
|48||10.2% chance of lowering Accuracy by 1 stage.|
|49||10.2% chance of lowering Evasion by 1 stage.|
|4A||10.2% chance of lowering a nonexistent glitch stat by 1 stage (does nothing).|
|4B||10.2% chance of lowering a nonexistent glitch stat by 1 stage (does nothing).|
Tail Whip Code
This bit of code is referenced in the special effect pointer table at 1E:4EF5, and uses the command "AnimationIdSpecialEffects". Since Tail Whip uses no sub-animations, it goes unused.
There exists an unused animation at 1E:672A which uses the command "AnimationShootManyBallsUpward" at 1E:5566. When bought in-game, this attack will slightly tint the screen while columns of three orbs rapidly move across the user's sprite. Game Genie codes 670-7E9-6E3 and 2A0-7D9-B32 will replace Pound's animation with this unused one.