So I've been "inspired" by the efforts of certain other people, and I've taken up the challenge of determining if Pokemon Red is beatable with any given unevolved pokemon using no items. Basically, the format is the same as most challenges of this nature are nowadays:
>The game starts with the selected pokemon as a starter: For sake of challenge, I'll attempt to pick the hardest path
>Only the selected pokemon is usable in battle: Other pokemon are usable outside of battle
>No items are allowed to be used in battle, only outside
>No Missingno-tier glitches: Badge glitch is fair game though
Thankfully, some of the work has already been done on this subject, so I don't have to try with the following pokemon:
>Bulbasaur: Completed at Level 69
>Charmander: Completed at Level 81
>Squirtle: Completed at Level 80
>Pikachu: Completed at Level 69
>Gastly: Completed at level 61 using only required battles
>Magikarp: Cannot complete challenge, gets walled at Lavender Tower. Minimum itemless level unknown
Insofar, I've personally attempted 2 pokemon so far, here's a summary of both experiences:
>Caterpie
Cannot complete challenge, gets walled at Lavender Tower due to lack of non-Normal moves. Was able to complete the rest of the accessible content (Erika, Rocket Hideout Giovanni, Fighting Dojo) at level 56. May be possible to do them slightly lower with good luck.
>Weedle
Cannot complete challenge, gets walled at Viridian Gym. Can complete all prior content (obviously). Compared to Caterpie,
>Was able to get through Viridian Forest quicker (level 10 vs level 16)
-Beat Brock at same level (26),
>Beat Cerulean Rival at similar level (~29-30)
Post too long. Click here to view the full text.