Pokémon: Blue Version is part of the first generation of games within its famous series, known for having a very large number of beneficial glitches. In fact, the game can be completed in less than one minute of in-game time by save data corruption as evidenced in the run of the Yellow Version, but that is not used here in favor of activating a similar glitch through more conventional means - if systematic breaking of the game can be called conventional.
This is an improvement of 04:03.09 over the previous run in this category, which used a couple different glitches and is worth checking out as well.
It is recommended that you read the author's comments to fully enjoy what's being done here.