This article is incomplete. Please feel free to add any missing information about the subject. It is missing: A large portion of the route.
The current Pokémon Blue "Catch 'em All" speedrun route obtains all 151 valid Pokémon using a variety of intended methods and glitches. The glitch used the most to obtain Pokémon is the LOL glitch. The run also performs the dry underflow glitch early on both the PC and the item pack, and uses the expanded item pack extensively to obtain Master Balls, Rare Candies and glitch items, warp around on the map, and do other memory corruptions.
The run also uses many luck manipulations. Most of them are to encounter specific Pokémon in their intended habitat, either by DSum manipulation or by hard-reset manipulations (including a Pidgey at the beginning for Brock Through Walls). Two other manipulations are used near the beginning, to get a desired Trainer ID and to death-warp from a trainer twice for a x255 item stack.
This page documents the route and analyzes the glitches used in detail.
Name the rival "AaR SS×" (the last character is a multiplication symbol, not a lower case X).
Set options to Fast/Off/Shift (this shows up in the expanded item pack later).
Pick Bulbasaur as the starter.
Brock Through Walls setup
There are two strategies to activate Brock Through Walls. The Pidgey strategy is faster, but is not consistent because it requires the Bulbasaur's Special stat to hit exactly 16. The PP strategy is slower, but consistent.
Either way, there are some steps that, for time reasons, are best done before activating Brock Through Walls.
Acquire six item stacks.
In the route, this is done by saving a Potion (appears in many places throughout the early game), buying 10 Poké Balls and 1 Paralysis Heal in Viridian City, picking up an Antidote in Viridian Forest, then buying 1 Burn Heal and 1 Escape Rope in Pewter City.
After winning the rival fight, the Bulbasaur will level up to L6, and the player should note its Special stat here.
If it has 13 Special, then it is most likely to hit 16 Special at L8 (75% probability). Therefore the player needs to kill an encounter (ideally L2/3 Rattata or L2 Pidgey) on the way to Pewter City.
If it has 14 Special, then it is most likely to hit 16 Special at L7 (43% probability). Therefore the player needs to avoid killing any encounter (Bulbasaur will level up after the Weedle Guy fight).
If it has 12 Special, then it is unlikely to hit 16 Special at all, so the player should either reset immediately, or commit to the PP strategy.
Put the Bulbasaur in slot 1 of the party, and the Pidgey in slot 2.
Mark sure Pidgey has 8, 10, 13, 15, 16, or 17 current HP (guaranteed if caught from the manipulation).
Some HP values may have unwanted complications (like disabling the Start menu, requiring a save from the PC). Again, it is best to just manipulate a 17 HP Pidgey.
PP strategy
Make sure the Bulbasaur is level 8, and has the following moves, in this order: Leech Seed (any amount of PP), Tackle (16 PP), Growl (36 PP).
Bulbasaur learns Leech Seed on level 7. It is best to kill two encounters (or one L4 Rattata) so that it learns Leech Seed before the Weedle Guy fight, and use the Weedle Guy fight to switch the move order.
Put the Bulbasaur in the last slot of the party.
Flash the party menu after doing the Pewter Gym skip.
For the PP strategy, remember to flash the party menu after the Pewter Gym skip, before talking to the Youngster.
Follow the red path below.
It is important to go up on the Route 3 map, rather than the Pewter City map. As the map above Route 3 is Route 4, this puts the player in the out of bounds area of Route 4 (more specifically, the phantom quadrant).
Walk left all the way to the tile on the right picture.
This tile pattern will appear early on during the travel, but 2 tiles higher. That is only a phantom copy of this place; keep going left.
This is actually a map connection tile on the right boundary of Route 4. After stepping on this tile, the player will be on the Cerulean City map, at an actually existing (but normally inaccessible) tile. The "cave" texture on the bottom-left corner is the "background tile" of Route 4, which is normally kept out of sight by strategically placed walls.
From here on, walk to the Vermilion Pokémon Center in a "normal" shortest path.
The preferred path is first walk straight down (through the out of bounds area of Route 5) to Saffron City, then turn right at the row below the Pokémon Center door, go to the column to the right of the door, then walk down (through the in bound portion of Route 6) onto the tile left of the Vermilion Pokémon Center door, and step right into the door.
Taking a warp ends the "walk through walls" effect.
Vermilion City
In the Pokémon Center, deposit Bulbasaur, and heal to set the death-warp destination.
On the way back to Route 11, read the Vermilion Harbor sign to avoid triggering a glitch meta-map script. (This results in a glitch text box with "13 ERROR.".)
Attempt to run away from the MissingNo.
If the player succeed in running away, the "defeated" flag of the leftmost trainer on Route 11 will be set. This will lead to some complications (mentioned below), but is still faster overall because it saves a trip from the Pokémon Center to the entrance of Route 11.
Toss 2 Escape Ropes to set the quantity to 127, then repeat the above steps.
If the player died to the first MissingNo., repeat the Spearow manipulation above. If the player escaped, the leftmost trainer will not be usable, so do a manipulation with another trainer instead.
Since the "13 ERROR." glitch text box points to the Route 11 trainer defeat flags, escaping from the first MissingNo. will set the first byte to 0x08 (TX_ASM), leading to a crash. Therefore, in this case the player should flash the Start menu instead of reading the Vermilion Harbor sign. (The guide states that reading the Harbor sign crashes even if the player died, but this is unconfirmed either way.)
Don't bother running away this time. Since we want to be at the Pokémon Center anyway, selecting a weak attack and (hopefully) being killed by MissingNo. first is faster.
PC underflow
After blacking out, enter the Pokémon Center, go to the PC, and open the item deposit menu.
Using the Escape Rope x255 stack, do dry underflow in the item pack first. The exact sequence of actions:
Swap the item in slot 3 (may differ depending on Potion strategies earlier) with the Escape Ropes, then deposit that item. (Item count = 5)
Deposit either all Potions or Poké Balls from slot 1 or 2, whichever is more convenient. (Item count = 4)
This duplicates the Escape Rope x255 stack, which helps with setting up PC underflow later.
Deposit the full stack of Escape Rope x255 in slot 2; there will still be a full stack in both slot 2 and slot 3. (Item count = 3)
Close the PC, and open the item pack from the Start menu.
Toss the top item stack twice. (Item count = 1)
Toss 253 Escape Ropes from slot 1.
Swap slot 1 with slot 2 twice. (Item count = 255)
Now use the expanded item pack to set up for the next segment of the route.
Swap Escape Rope x0 with a stack of #j. x0 between #j. x129 and Master Ball x128.
Here "battle pending" is the same meta-map script used by the trainer escape glitch. As can be seen, the primary purpose of this segment is to set up special encounters on various maps. The secondary purpose is to get some useful items in our item pack.
Exit through the left doormat tile (it is actually the right doormat tile; what we did with our expanded item pack messed up with the graphics) and warp to Celadon City.
Celadon Mart
At this point, our item pack should contain:
Unimportant item (Potions or Poké Balls)
Escape Rope x253
#j. x96 (First we withdrew 1, then a stack of 255 made it 0, the second stack of 255 put 99 here and 156 in another slot below, and the third, fourth, and fifth stacks of 255 each subtracts 1 from the quantity)
Sell the stack of #j. x96 in slot 3 for 499999 Pokédollars. (Item count = 5; Master Ball x255 duplicated)
After dying 3 or 4 times on Route 11, the player should have either 33 or 16 Pokédollars left. This will give just enough money to buy everything needed for the route.
Buy the following items (quantities close to 99 are faster to select by pressing Down instead of Up). (Item count = 20)
Although X = 39 is out of bounds, the player does not really go out of bounds, because the map view pointer is not updated. Instead, the player has a "out-of-bound experience" where all NPCs and warps disappear (because they are shifted out of the screen), but the background tiles, including their collision properties, work as normal.
Get on the bike (which is possible because the "overworld" tileset allows cycling), and move down and right 1 tile each.
Open the item pack again.
Swap Revive x93 just bought with TM41 x80 a few slots below the normal item pack.
Swap Revive x93 again with Master Ball x5 put there during the first expanded item pack session.
Note: "Map music ID" is only used when starting the music (e.g. after getting off the bike); "valid map connections" and "north connection preview data source" are only used when first loading the map.
Walk up one step.
Because the player is now at Y = 0, stepping up triggers the north map connection, sending the player to the Power Plant. Since the tileset has changed, the game thinks the player has taken a warp, and places the player at the entrance of the Power Plant.