You must know how to itemclimb (bind jump to your mousewheel and spam E to climb on props) and have a knowledge of Portal physics.
bind mwheelup "+jump"
bind mwheeldown "+jump"
You might also learn how to portal peek (the action to go through a portal while shooting a portal).
The transition between elevators can obviously break, some pistons are upside down so they are invisible especially on E00, orb receivers are offset but it's not a big deal.
I am kind of sad that the beggining has that much itemclimb but this is forced by the architecture of the Aperture Laboratories that isn't made to be walked on the ceiling.
The main categories I imagined for this game are Legacy and Glitchless, but Glitchless without counting itemclimbing as a glitch since it's an intended mechanics.
I am sorry about Out of Bounds and Inbounds runner, they might have fun routing saveglitches though.
Finally, I want to add that all maps are finishable.
PackSciences
