Oh, I've thought this is the TAS already.
Well, a TAS would be wildly different than this. The fastest way to increase your movement speed is air strafing rapidly. I couldn't calculate the "golden ratio" between number of air strafes and the degree change depending on actual movement speed, but solely this trick would save a lot of time.
An easy way to understand this is that the maximum speed Gordon can go is probably ~
edit4: much more than2000units/speed, while the "running" speed is around ~400unit/speed (don't trust me, I played HL ages ago).
The TAS would aim to pass each door with that maximum speed. Also when "hitting a door", a (standup) countjump should be used for fastest speed recovery (ducking for 1 frame, making a 180 degree turn with correct turning speed and jumping once touching the land). Oh and I don't even mention FPS_MAX trickeries.
btw,
http://www.youtube.com/watch?v=VtI5HM7GVGY#t=48 -> hitting the wall or it's just the map transition?
around ~4:30, in theory, wallsliding gives a very slight boost while strafing there, but it's very hard to pull it off in real time and probably a TAS could make better strafes than falling on wall.
I know it's a TAS once someone able to pull objects while boosting off it infinitely, same way as in ~4:44.
At ~7:48, a wall bug would be better (90 degree facing towrads a wall, forward and duck). Next scene why not jump on scientist and barney head?
Also I would watch a multiplayer speedrun, where players boosts through walls in narrow areas, so one player can advance scripts/entities/transitions while the other one can go to the next part, but people should argue about playing single player with multiple players.
edit: tripmine can't be used to boost through walls? probably an NPC who can jump is required to do that like Barney.
edit2: or snarks?
edit3: "jumpbugs: 14"? I admin I didn't watched it fully, but was there actually a jumpbug (jumping down to a platform while ducking,release duck and jump when 2~4 units above the floor)? I saw mostly edgebugs (falling no a slope wall to avoid taking damage and saving horizontal speed) and "slow wallbugs" (jumping between 2 walls closing in 45 degree)
edit4:
http://wiki.sourceruns.org/wiki doesn't contains wallbug which would save time (I wrote it for 7:48 in this post).
http://wiki.sourceruns.org/wiki/Sharking depends on sv_airaccelerate and another variable (sv_airmove?), so it's different between games
http://wiki.sourceruns.org/wiki/Object_Boosting totally right, the game reduces velocity if it reaches more than 4000, so if you maintain it 3999.999, you can stay on that value.
