This is a tool-assisted speedrun. For more information, see http://tasvideos.org/3915M.html. TAS originally published on 2019-03-06.
Portal for Commodore 64 is a 2018 unofficial "demake" of the original Portal game developed and published in 2007 by Valve Corporation. The "demake" inherits the basic mechanics of the game and adapts them for a simplified 2-dimensional world.
Gameplay still consists primarily of a series of puzzles that must be solved by teleporting the player's character and simple objects using "the Aperture Science Handheld Portal Device", a device that can create inter-spatial portals between two flat planes.